It’s arguably the most full-featured single CPU desktop motherboard ever produced. It also happens to be cooled with heatpipes and features a complex chipset configuration. We put the Asus A8N32-SLI Deluxe under the microscopes in the SPCR lab to come up with a thorough thermal / power profile of this impressive motherboard.
February 9, 2006 by Devon
Cooke and Mike Chin
| Product | ASUS A8N32-SLI DELUXE Fully Loaded Socket 939 Motherboard |
| Manufacturer | ASUSTeK Computer Inc. |
| Street Price | US$200~220 |
As a general rule, silencers don’t expect that much from their motherboards. There
are really only two essential items:
- It needs to be stable, even when the temperature rises
- It needs to be silent — tiny 40mm banshee fans on the north and/or
southbridges are a no-no.
Stability is a bit of a shot in the dark. It’s almost impossible to judge the
stability of a motherboard until it’s been on the market for a few months,
and even then it’s best to stay with established technology and popular models.
Noise, on the other hand, is very easy to judge: Motherboards without fans
are good, motherboards with fans are bad.
The retail box goes in for the understated, classy look.
Enter the ASUS A8N32-SLI Deluxe. Although not targeted specifically at silencers,
it does address these two requirements.
- Stability: It’s based on a modification of the established nForce4 chipset, and ASUS
is about as well-known as they come. - Quiet: It is one of the few passively cooled nForce4 boards on the market, thanks
to an exotic system of heatpipes.
On closer examination, the board has a couple of quirks that makes it
interesting to silencers:
- It is one of the first to feature an eSATA (external SATA) connector,
which makes it possible to use an external drive without a drop in performance. - It is reputed to be highly efficient thanks to the fancy eight-phase VRMs
for the CPU. This means it should run cooler and require less airflow (and
noise) to cool properly.
It also doesn’t hurt that the A8N32-SLI Deluxe is about as fully-featured as
they come… and for >US$200, it had better be!
Its major selling point (as per ASUS’ marketing department) seems to be dual
16x PCIe slots that can both run at 16x. Translation: More bandwidth available
for dual GPU setups, and, theoretically, higher frame rates. In reality, this
advantage seems to be mainly theoretical, as reported by several other
web
sites
that examine performance, not noise. To be fair, the additional bandwidth my
come in handy later on when quad-core GPU setups hit the market, although few
silencers will want to deal with the excessive amount of heat that such setups
are likely to produce.
The additional 16 PCIe lanes required to implement this design are actually
too much for the original nForce4 chipset to handle. For this reason, the A8N32-SLI
uses a revised version of nForce4, called nForce4 SLI x16. Aside from
requiring a slightly different set of drivers, the main change seems to be the
addition of a second chip of silicon to manage the extra bandwidth. Needless
to say, this takes up space on the motherboard, and requires a more complex
cooling system.
Shining copper heatsinks add a lot of mass — it weighs about twice as much
as usual.
Click image for a higher resolution view.
The rest of the features, while extensive, are comparable to other high-end
boards. There are too many to cover in detail without getting very boring,
so we will list the specs and touch only on the highlights.
| ASUSTeK A8N32-SLI Deluxe Specifications | |
| CPU | – Socket 939 for AMD Athlon™ 64 FX/64 X2/64 and Sempron™ processor – Supports AMD 64 architecture that enables simultaneous 32-bit and 64-bit computing – Supports AMD Cool ‘n’ Quiet! Technology |
| Chipset | – NVIDIA® nForce4 SLI x16 – Northbridge: NVIDIA® nForce™ SPP 100 – Southbridge: NVIDIA® nForce4 SLI |
| Front Side Bus | 1600/2000 MT per second |
| Memory | – Dual-channel memory architecture – 4 x 184-pin DIMM sockets support unbufferred ECC/non-ECC DDR400/333/266 memory modules – Supports up to 4 GB system memory |
| Expansion Slots | – 2 x PCI Express™ x16 slots with Scalable Link Interface (SLI™) support at full x16, x16 mode – 1 x PCI Express x4 slot (supports x4/x1 card) – 3 x PCI slots (PCI 2.2) |
| SLI | SLI™ mode supports: – 2 x identical SLI™-ready PCI Express™ x16 graphics cards (Note: In SLI mode, the PCI Express x16 slots work at the full bandwidth of x16 each, for a combined bandwidth of x32.) – ASUS Soft SLI Bridge – ASUS EZ Plug™ – ASUS PEG Link for dual PCI Express graphics cards – ASUS Two-slot thermal design |
| Storage | NVIDIA® nForce4 SLI supports: – 2 x Ultra DMA 133/100/66/33 connectors for up to four IDE devices – 4 x Serial ATA devices (3 Gb/s) – NVRAID for RAID 0, RAID 1, RAID 0+1, RAID 5, and JBOD configuration that spans across Serial ATA drives Silicon Image® 3132 SATA controller supports: – 1 x Internal Serial ATA device (3 GB/s) – 1 x External Serial ATA device (3 GB/s) (for SATA On-The-Go) – RAID 0 and RAID 1 configurations |
| USB | Supports up to 10 USB 2.0 ports |
| AI Audio | Realtek® ALC850 8-channel CODEC – 1 x Coaxial S/PDIF out port – 1 x Optical S/PDIF out port – Supports Universal Audio Jack (UAJ®) Technology – Supports Audio Sensing and Enumeration Technology |
| IEEE 1394 | TI® 1394a controller supports 2 x IEEE 1394a connectors at midboard |
| Network | – Marvell® PCI Express Gigabit LAN controller – Marvell® Gigabit LAN PHY – NVIDIA® nForce4 SLI built-in Gigabit MAC with external Marvell Gigabit LAN PHY supports: – NV ActiveArmor – NV Firewall – NV RIS (Remote Installation Service) – AI NET |
| Overclocking | Intelligent overclocking tools: – AI NOS™ (Non-delay Overclocking System) – AI Overclocking (intelligent CPU frequency tuner) – ASUS PEG Link (automatic performance tuning for single/dual graphics cards) – ASUS AI Booster Utility Precision Tweaker supports: – DIMM voltage: 13-step DRAM voltage control – Core voltage: Adjustable CPU voltage at 0.0125 V increment Stepless Frequency Selection(SFS) allows: – FSB tuning from 200 MHz to 400 MHz at 1 MHz increment – Memory tuning from 400 MHz to 800 MHz – PCI Express frequency tuning from 100 MHz to 200 MHz at 1 MHz increment Overclocking protection: – ASUS C.P.R. (CPU Parameter Recall) |
| Other Features | – Stack Cool 2 – ASUS SATA On-The-Go (External Serial ATA port on the rear panel – ASUS 8-Phase Power Design – ASUS Fanless Design – ASUS AI Overclocking (Intelligent CPU frequency tuner) – AI NET network diagnosis – ASUS CrashFree BIOS 2 – ASUS Q-Fan2 – ASUS MyLogo2 – ASUS EZ Flash – ASUS Multi-language BIOS – ASUS CPR (CPU Parameter Recall) |
| Manageability | WfM2.0, DMI2.0, WOL by PME, PXE, RPL |
| BIOS Features | 8 Mb Flash ROM, AMI BIOS, PnP, DMI2.0, SM BIOS 2.3, WfM2.0 |
| Power Requirements | – ATX power supply (with 24-pin and 4-pin 12 V plugs) – ATX 12 V 2.0 compliant – ASUS EZ Plug (When using two graphics cards and a 20-pin ATX PSU or, if the two graphics cards do not have auxiliary power.) |
| Rear Panel | – 1 x Parallel port – 2 x LAN (RJ-45) ports – 4 x USB 2.0 ports – 1 x External Serial ATA port – 1 x Optical S/PDIF Out port – 1 x Coaxial S/PDIF Out port – 1 x PS/2 keyboard port (purple) – 1 x PS/2 mouse port (green) – 8-channel audio ports |
| Internal Connectors | – 1 x Floppy disk drive connector – 2 x IDE connectors – 4 x NVIDIA nForce4 Serial ATA connectors – 1 x Silicon Image Serial ATA connector – 1 x Serial port connector – 1 x 24-pin ATX power connector – 1 x 4-pin ATX 12 V power connector – 1 x 4-pin ASUS EZ Plug™ connector – 3 x USB connectors for additional six USB 2.0 ports – 1 x CD IN/AUX connector – 2 x IEEE 1394a connectors – 1 x GAME/MIDI connector – 1 x Chassis intrusion connector – 1 x Front panel audio connector – CPU, Chassis (x2), Chipset (x2), Power fan connectors – System panel connector |
| Support CD Contents | – Device drivers – ASUS PC Probe II – ASUS Update – ASUS AI Booster – NV RIS – NV Firewall – NV RAID – Anti-Virus Utility (OEM version) |
| Form Factor | ATX form factor: 12 in x 9.6 in (30.5 cm x 24.5 cm) |
FEATURE HIGHLIGHTS
Lots of goodies…
As the number of different devices you can plug into a motherboard have increased,
the real estate for ports on the rear panel has become jam-packed. Because
of this, a number of the usual ports are missing. Fortunately, ASUS has supplied
them on PCI brackets instead, so they’re all there if you need them. Included
on the brackets are two Firewire ports (a 6-pin and a 4-pin), a serial port,
a game/MIDI port and two additional USB 2.0 ports. In place of these older ports,
there are a second Ethernet port, two S/PDIF ports (one optical, one coaxial),
and the aforementioned eSATA port.
What is eSATA? eSATA is an extension of the SATA specifications that is designed
to allow external devices to take advantage of the full 1.5 (or 3.0) Gbps interface
bandwidth of SATA. If superior technology is the only criteria, it should replace USB 2.0 and Firewire
as the interface of choice for external storage. A
technical brief of the technology can be found on the SATA-IO web site.
eSATA cables can be up to two meters long, and, unlike internal SATA cables,
are rugged enough for repeated uses. There is also a version, called xSATA,
that will extend the maximum length to around ten meters. Unfortunately, eSATA
does not carry power, so an external power source will be needed for external
drives.
Why is this of interest to silencers? It would allow systems to be run without
any internal drives, as the system drive could be located elsewhere. More importantly,
it would mean that the system drive need not be silenced within the system itself.
Without the space and mounting constraints of a computer case, it would become
much easier to find ways to reduce drive noise.
No Firewire, but everything else is ready to go. Note the red eSATA port.
The inclusion of the second Ethernet port is a little odd — it seems unlikely
that many users will use both ports, and the space for the second port could
have been better used by integrating the Firewire port. They use two different control chips — one from NVidia and one from
Marvell, and they have slightly different features. For example, the NVidia
port comes with a hardware firewall, while the Marvell port can detect cable
faults via a utility in the BIOS. There is considerable potential for user error
here. Unless the user is aware of the differences (and which features belong
to which port), he may be led to believe that he has firewall protection when
he does not, or mistakenly believe that he has a cable fault. For the record,
the nVidia port is on the left and the Marvell port is on the right.
| Asus Compatibility the Antec NeoHE Power Supplies? The A8N32-SLI Deluxe was one of many Asus motherboards which appeared to have a serious compatibility problem with the Antec NeoHE power supplies. Our first NeoHE PSU samples (circa Oct 2005), both retail package samples and the 430W models included with the Antec P150 case, refused to play nice with the A8N32-SLI, usually booting only for 10~40 seconds before powering down. The most recent NeoHE samples, revision A3, were received around Christmas 2005. These latest samples work quietly without any issues with the A8N32-SLI Deluxe, the Asus A8N-SLI, and Asus A8N-VM CSM — all the Asus socket 939 motherboards on hand in the SPCR lab. We were informed by Antec that not all the PSUs are marked with a revision number, but you can figure out the date of ex-factory from the serial number. One of our A3s has this number: S05110081185. The 0511 means it was shipped from the factory in 2005, November. So any NeoHE whose serial number starts with S0511, S0512 or S06 should be perfectly compatible with Asus boards. |
HEATSINKS AND COOLING
The A8N32-SLI is one of very few nVidia-based boards that is passively
cooled. This is possible thanks to an elaborate system of copper heatpipes and
heatsinks that transfer the heat away from the chipset bridges. Of course, it’s
not enough just to move the heat around. Eventually, the heat needs to be exhausted
from the case.
To this end, the main heatsink for the chipset is located between
the CPU socket and the rear connectors. The basic idea is to move the heat from
the chipset into the exhaust airflow path from the CPU heatsink, which is almost
guaranteed to have a fan. Even if the CPU is being cooled passively however,
the case fan in a well designed system should provide airflow in the right place.
If it doesn’t ASUS has included a small blower that can be used as a last resort.
A stack of copper fins puts the heat from the chipset in the exhaust of the
CPU heatsink.
How does the heat get up to that part of the board, you might
ask. Or, if you’ve already looked at the pictures, you might not, since you’ll
already know that the answer is heatpipes. Two copper blocks — one each
on the northbridge and the southbridge — are used in place of the more
conventional aluminum heatsinks, and two heatpipes, one from each chip, carry
the heat up to the top of the board.
Copper blocks with heatpipes instead of aluminum heatsinks.
It should be no surprise that the all-copper design is quite massive in both
size and, well, mass. This is by far the heaviest motherboard we’ve encountered
— it’s so heavy we were almost afraid to move it around much in case it cracked
under its own weight!
Perhaps a bigger concern is how the layout of the heatpipes will affect compatibility
with various heatsinks. As the photo below shows,
clearance is a bit tight around the CPU. Fortunately, the cooling system has
a low profile, and most of the large heatsinks are narrower around
the bottom, as they should be.
Another potential tight spot is above the top PCIe slot. There is not a lot
of clearance between the slot and the main chipset heatsink, and double width
cards with big heatsinks on the back side of the card may not fit properly. Large
graphics cards may be installed normally in the lower PCIe slot, so this issue
probably only applies to users with more than one video card.
Seemingly limited clearance around the CPU…
…isn’t really an issue, as the huge Scythe Ninja fits fine and has plenty of clearance.
As long as the board is installed in a ATX tower case with conventional
airflow — especially the back panel exhaust fan — the heatpipes should have no problem keeping the chipset cool. However,
there are potential problems that could arise in a nonstandard setup.
Some of these have been mentioned already: The motherboard is not recommended
for use with passive heatsinks or watercooling setups unless additional airflow
is provided for the chipset.
In addition, cases that orient the motherboard horizontally or
upside down, such as HTPC and some enthusiast cases (Lian-Li PC-V series and Silverstone TJ06 come to mind), may affect the efficiency
of the heatpipes. The reason for this is simple: Heatpipes work best when gravity
helps return the refrigerant from the condensor to the evaporator (in heatpipe lingo). In other words, the
source of the heat should be below the cooling fins that dissipate the heat. That doesn’t mean the heatpipes won’t work otherwise; as long
as there is a difference in temperature between the source and the exhaust, the coolant will cycle, even if more slowly than usual. But, the cooling system is designed with the
assumption that it will be installed in a conventional case, and it’s probably
best not to tinker with it without a lot of planning and testing.
Vital Statistics: YD124515MB, DC12V, 0.13A.
As a safety precaution, ASUS has included a small blower that is designed
to clip onto the chipset heatsink if the cooling is inadequate. Oddly enough,
this “safety feature” comes with a warning that threatens instability
if the fan is installed when it is not needed. This isn’t as crazy as it sounds:
The blower is quite tall, and could actually interfere with airflow in a well-designed
system.
The blower is branded Y.S. Tech, but the model number does not show up anywhere
on the internet. Most likely, it is a custom design for ASUS. Its noise signature
is fairly benign — better than most northbridge heatsinks — but it’s
still louder than most people will want from a passively cooled board. Because
the passive design is the primary reason why many will consider the A8N32-SLI
Deluxe, we did not bother doing extensive acoustic testing on the
blower.
The backside has an ASUS logo. The blade design is similar to those found
on some recent nVidia VGA cards.
Although the heatpipes carry the bulk of the heat from the motherboard,
there is one heatsink that they do not reach. There is a narrow aluminum heatsink
parallel to the top of the board that cannot count on heatpipes to help it out.
This heatsink is for the MOSFETs that help supply power to the CPU. Although
they do tend to get quite hot, this is the only motherboard we’ve seen that
has a heatsink specifically for them. Perhaps it is needed for the eight-phase
power regulation that ASUS boasts about…
Like the the main copper heatsink, the aluminum heatsink sits
beside the CPU socket where it can take advantage of the airflow coming off
the CPU cooler. A power supply with a bottom-mounted fan may also provide some
airflow around it, as will a rear-panel exhaust fan.
One last heatsink, this one aluminum.
BIOS
The feature list for the BIOS is worth an article of its own.
Not surprisingly, it is geared towards overclockers, and
almost every voltage and clock speed can be tweaked. For any Athlon 64 board these days, Cool ‘n’ Quiet support is a given. For a silencer,
there are only two additional features that really matter:
- Undervolting and underclocking potential.
- Good quality fan control.
In addition to the basic do-it-yourself and “revert to stock” settings,
there are several other options for “automated” overclocking and dynamic
frequency control. Unfortunately, all of these are geared towards raising frequencies
and voltages, not reducing them, so they are of limited use to silencers.
Five different overclocking modes are available.
The enormous range of possible configurations make navigating
the BIOS a bit of a nightmare, especially since options appear and disappear
(or become selectable) based on what other options are selected. Even with everything
set to manual, it still took a few tries to discover how to change the processor
voltage. The key: Voltage can only be changed when Cool ‘n’ Quiet is disabled.
If you can find the proper settings, the full range of processor
voltages, multipliers, and HTT bus speeds can be tinkered with, as well as a
few that are best left alone. The following adjustments are possible:
- Processor Voltage: 1.000 ~ 1.5625 V in 0.0125 V increments
- FSB: 200 ~ 400 MHz, in 1 MHz increments
- Processor Multiplier: 5x ~ Processor maximum, in 0.5x increments
Underclocking is possible only by lowering the multiplier; the FSB cannot be
lowered below the stock value of 200 MHz.
A full range of voltage adjustment, from low…
…to high
Fan control on the A8N32-SLI Deluxe is very simple. There are two options:
Enabled and Disabled. That’s all you get. No trigger temperatures, maximum speeds,
or even a manual mode that lets you set the speeds to a constant value. Even
worse, it is far from clear which headers are controlled, and only three of
the six (!) fan headers on the board show up in the BIOS. For casual users,
Q-Fan may provide a quick and dirty way to regulate fan speed, but there’s not
enough here to satisfy the tinkerers or quiet lovers.
This is the extent of the fan control options.
One final feature is so unusual that it bears mentioning just for the novelty.
The Marvell ethernet port comes with the ability to check for cable faults,
and the utility to do this is included in the BIOS itself. It can even be set
to do a check whenever the system boots, so the user will be notified immediately
if there is a problem. It can even identify how far down the cable the problem
is occurring!
This feature has been a part of Marvell’s software package for some time, but
this is the first time we’ve seen it integrated into the BIOS itself. As mentioned
before, this feature is available only on the Marvell-controlled port; the utility
will not find faults on cables plugged into the nVidia controller. However, Windows XP automatically signals when an ethernet port is unplugged.
Built-in checking for ethernet cable faults.
EIGHT PHASE POWER EFFICIENCY
Methodology
As a general rule, a motherboard does not consume a large amount of power, but
when it does, it’s almost always the voltage regulation module (VRM) that
is at fault. It’s a simple matter of physics: A high power processor requires
a voltage around +1.5V. The PSU supplies only +3.3V, +5V,
and +12V. Therefore, the motherboard must convert one of these voltages into
a form that the processor can use; it is +12V line that’s generally used to supply the processor. These days, almost every motherboards pull this +12V from the AUX12V line — the juice provided via the 2x12V connector.
There are inherent losses
in the conversion from +12V to +1.5V. The total power drawn by the motherboard is always higher
than the power required by the processor. The excess is lost in the form of
heat. The less efficient the conversion, the more heat is produced, and the
more power is drawn by the system overall. Motherboards that can do the voltage
conversion efficiently run cooler and require less power under load. Typical
motherboards tend to be between 65-80% efficient.
Let’s put that in perspective. Assume that a processor draws 75 watts under
load (a conservative estimate for many of today’s processors). A motherboard
with a VRM that is 80% efficient will add almost 20 watts of additional heat to the system.
A 65% efficient motherboard may add double that amount!
The A8N32-SLI Deluxe has the potential to cut the amount of
heat in the system significantly — if it lives up to its claim of being
highly efficient. How efficient is “highly efficient”? We just had
to find out, so we decided to compare the A8N32-SLI against another highly regarded
nForce4 motherboard.
In this comparison, the same components (or components with
equivalent power requirements) were installed on both systems, and the total
power draw from the AC source was measured. Any differences in power consumption
would be attributed to the motherboards alone.
The following components were used for the comparison:
- SilverStone Strider ST65F
560W power supply — on the test bench, 78.4% efficient at 90W output, 80.7% efficient
at 150W output - AMD Athlon 64 X2 3800+ — Toledo core, revision E6
- 2 x 512 MB OCZ PC3500 DDR SDRAM
- Thermalright HR-01
— cooled by a Nexus 120mm fan plugged into the CPU fan header - AOpen Aeolus 6800GT DVD256MV — cooled by an Arctic Cooling NVSilencer
5 (Rev. 3) - Samsung Spinpoint P120
SP2504C hard drive
Test tools included:
- AC power was measured with an Extech Power Analyzer / Data Logger 380803
power meter. This is a new welcome addition to our lab that allows more precise, unmanned, long term AC power monitoring. - Processor voltage was monitored using SpeedFan
4.27 - Processor specifics were documented using the incredibly useful utility A64 TCaseMax v1.18 by Arthur Liberman, who runs the web site www.thecoolest.zerobrains.com. Please see the sidebar for more details. A screen capture of the result details the processor specifics:
What the above tells us is that this is a fairly cool running processor. A TDP of 65.6W is pretty good for a dual-core processor of this caliber. It also tells us that this is the maximum power the processor will draw under full load with the Vcore at 1.35V.
| SIDEBAR: AMD64 TCaseMax v1.18 Text as posted by Arthur Liberman in the www.thecoolest.zerobrains.com/forums “This is a new type of program, which checks AMD64 CPUs for their maximum rated case temp or TCaseMax and reports the TDP which corresponds to the processor in question.”On most AMD processors TCaseMax and TDP values are constant, and depend on CPU type and model, but on the E Revision chips, both this value and the default voltage are variable.These are the chips that have variable values:
“What this all means is this: On 90nm manufacturing process, the power leakage of transistors on individual processors differs greatly, this is why AMD implemented TCaseMax. Each CPU has a different TDP rating, here’s how it works: “A program reads the TCaseMax value off the CPU, then depending on the processor (CPU type like A64, Opteron;CPU Rating like 3500+, 146) it finds the processor’s Thermal Profile (If you download the “AMD Opteron™ Processor Power and Thermal Data Sheet” and look at pages 10-11 you’ll see the different thermal profiles). When the thermal profile is determined, the program finds the TDP rating that corresponds to the CPU’s TCaseMax value. “So in a few words, the higher the TCaseMax, the higher the TDP of a processor will be (the transistor leakage is higher), so the processor will run hotter. Several people have reported that the Opterons rated at 71C TCaseMax were pretty hot. On the other side these processors will be able to reach higher clock speeds. “That is why we see that on average processors with higher TCaseMax can usually reach higher CPU speeds when overclocked.” |
The ASUS A8N32-SLI Deluxe was compared against a DFI LanParty NF4
Ultra D. The motherboards were tested in three states:
- Idle, with Cool ‘n’ Quiet
- Idle, without Cool ‘n’ Quiet
- Under load, running two simultaneous instances of CPUBurn
Now, here’s where it gets hairy: The A8N32-SLI Deluxe does not run the processor
at its stock voltage of 1.35V. Out of the box, it was running slightly high,
at 1.39V. This slight difference is enough to bias the test results, so the
processor voltage was adjusted down manually by 0.0375V, resulting in a final
voltage of ~1.36V — close enough. But, there’s a catch. The voltage cannot
be manually adjusted while Cool ‘n’ Quiet is enabled, which meant that the Cool
‘n’ Quiet test could not be completed. In the end we tested it with the Vcore at default.
Test Results
| EFFICIENCY COMPARISON: TEST RESULTS | ||
| Processor State | ASUS A8N32-SLI Deluxe | DFI LanParty NF4 Ultra D |
| Idle (CnQ) | 116W* | 97W |
| Idle (No CnQ) | 141W | 105W |
| Load (2xCPUBurn) | 176W | 159W |
| *Processor Voltage for this test was 0.04V higher than stock | ||
Surprised? We sure were! We were so surprised that we re-ran the test a couple more times —
and got the same result.
The absolute numbers
are not in question — only their meaning. The smallest difference between
the two boards was 17 watts, at full CPU load. That is a significant amount of heat. In idle,
where most systems spend the majority of their time, the difference was 36W, more than
double that. Mind you, most people will run CnQ, and the difference then drops to 19W.
The results of this test raised more questions that it answered. How could
the ASUS board, with its eight-phase power circuitry, draw so much more power
under the same conditions than the DFI board? This question forced us to go
back and reexamine our methodology. No conclusions
could be drawn, but a few things seemed clear:
- A higher total power draw doesn’t necessarily mean that the
motherboard is less efficient. The 36 watt difference between the two motherboards
at idle is far too much to attribute to differences in motherboard VRM efficiency alone. - The two motherboards do not have identical chipsets.
One other item that was examined was the power testing results for the Asus A8N-SLI Premium board that was used in a PC built for an old friend of Mike Chin in Thailand. A different PSU was used, but its efficiency is slightly lower than the one used here; most other components were reasonably close: The same model processor, a single HDD, a gig of RAM, and a slightly less power hungry video card, the 6800GS. Here are the results, from the table on page six of that article.
| Asus A8N-SLI Premium (Thailand system) | |
| Processor State | Total AC Power |
| Idle (CnQ) | 94W |
| Idle (No CnQ) | 99W |
| CPUBurn, Prime95 and 3DMark05 simultaneously | 190W |
The maximum power draw of 190W can be discarded because it was a peak measured while the system was under higher load than the other two boards tested here. However, the idle power measurements are much closer to those of the DFI LanParty NF4 Ultra D board than the Asus A8N32-SLI Deluxe. Why?
POWER EFFICIENCY (continued)
When the specifications were re-examined, what we found is that the LanParty NF4 Ultra D runs the nForce4 Ultra chipset, and the A8N-SLI Premium runs the nForce4 SLI chipset. In contrast, the A8N32-SLI Deluxe is equipped with three chips:
– NVIDIA® nForce4 SLI
x16
– Northbridge: NVIDIA® nForce™ SPP 100
– Southbridge: NVIDIA® nForce4 SLI
We could not find any reference to nForce SPP 100 on nVidia’s web site. It is possible that this is integrated in the SLI x16 chip. On the nF4 family page, nF4 SLI x16 is described as a chipset that provides up to 38 lanes for PCI Express and suppports SLI x16. This is double the bandwidth of nF4 SLI or nF4 Ultra, both of which provide 20 lanes for PCI Express and 8X SLI. The SLI x16 chip seems bound to be more power hungry than either of the narrower bandwidth SLI or Ultra chips.
The A8N32-SLI Deluxe clearly runs two chipsets, not just one. A close visual comparison of this board against the LanParty NF4 Ultra D and the A8N-SLI Premium confirms this. And now the power numbers make sense.
One hot chip.
Still one hot chip.
Two hot chips!
Despite the fanfare surrounding the efficiency of the eight-phase power circuitry, the A8N32-SLI
Deluxe is a power hungry motherboard. The extra bandwidth in the PCIe lanes in SLI mode may well help gaming performance, but the gain comes at a price that’s paid even when only one video card is used. A near-20W increase in power consumption even in idle seems a high price to pay.
FINAL THOUGHTS
All in all, the Asus A8N32-SLI Deluxe is a bit of a mixed basket.
It’s passively cooled and runs both SLI and SLI x16 chips, which makes it quite a rarity. We have no doubt that, at least in theory, the additional bandwith
for PCIe-16X in SLI mode has a performance benefit with the fastest video cards. The price for this potential added performance at the stratified extreme of PC gaming comes
at the price of high power consumption (read: Heat!), even if you’re only using one video card.
It’s true that at least the board is silently cooled with the very nicely implemented heatpipes, but the heatpipes may not work well in all configurations.
The A8N32-SLI Deluxe is very full-featured, and the BIOS allows almost any
value to be tweaked and tinkered with. Probably as a direct result of the great number of options, navigating the BIOS
is rather tedious, and it is not always clear how setting one option can affect
what other options are available. In this performance-oriented board, it is not unusual that the FSB cannot
be dropped below 200 MHz, but we’re glad to see that underclocking is
possible by changing the CPU multiplier.
The inclusion of external SATA unusual and welcome, but the reality is that
there are not enough eSATA products on the market today to truly take advantage
of it yet. By the time these devices become widespread, the A8N32-SLI Deluxe probably will
be old news, and other models will have taken its place.
As the top ASUS enthusiast board, the A8N32-SLI Deluxe is guaranteed to have
its followers. If you’re looking for
a SLI 939 board that does everything, and passive cooling is a necessity, this board
can certainly deliver. But, if you don’t need the all the features and just want a
board that is quiet and cool, you’ll probably want to keep looking. We think the less costly but still feature-packed fanless Asus A8N-SLI Premium is a better bet for silencers.
| PROS * Does everything | CONS * Power hungry |
Much thanks to ASUSTeK
for the opportunity
to review this motherboard.
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