And so my Dothan Pentium-M HTPC adventure begins..

[wumpus]

Based on Ralf and Mike's excellent article:

http://www.silentpcreview.com/article218-page1.html

And my desperate need to have a HTPC that can run in a semi-enclosed space with crappy ventilation, I ordered the following:

AOpen i855GMEm mobo


1.6ghz Pentium-M "Dothan" (2mb l2 cache)
(c'mon, do you really need to see an image of this?)

Alpha PAL8952 P4 heatsink


I was really torn as to what heatsink to use, since I am planning to go totally passive on the CPU heatsink. The Zalman circle thing isn't an option for the MicroATX layout I plan to use because it's so friggin' huge; I needed something that would A) stay within the retention bracket square and B) be amenable to passive cooling, eg, have a relatively open set of fins. I thought the Alpha might be a good way to go. Ralf, your thoughts?

Now, my current HTPC case has some pretty serious problems, and it's become depth constrained in our current living room media furniture. So I needed a new MicroATX case with:

1) dimensions LESS than the Coolermaster ATC-620
2) four total drive bays (between 5.25" and 3.5")
3) NO depth-increasing front cover panel

This is very, very difficult to find! I spent hours looking. I finally settled on this:

Logisys acrylic HTPC case


Yeah, kinda blingy, but I was desperate. Still better looking than a lot of HTPC cases in my opinion, such as that hideous HT-100 that won the Anandtech December HTPC case roundup. Sadly, unlike the ATC-620 this doesn't accept standard PSUs so I had to buy a MicroATX-specific PSU. I chose this one based on fan size:

Sparkle 180w MicroATX PSU


I'll let you guys know how this goes. Should be interesting. Yeah, it's a little expensive ($400 for just the mobo+CPU!) but the way I figure, it's worth it. How else could you spend $400 to cut your power budget by over HALF. That's 70 watts for the Barton 2500+, versus ~17 watts for the Dothan 1.6ghz! (I guesstimated 1.6ghz Dothan wattage since Ralf and Intel only quote 21w for the fastest Dothan @ 2.0ghz)

[wumpus]

Shoot, I should have noticed that the GamePC 90nm processor comparison does quote comparative power consumption numbers:

Power Consumption
AMD Athlon64 "Winchester" 1.6 GHz vs Intel Pentium-M "Dothan" 1.6 GHz

Load (folding, cpu only)
132w -- 95w

Idle (full clock):
125w -- 81w

Idle (speedstep/CnQ):
117w -- 75w

(edit: crappy incorrect power numbers removed) I'll post better, direct comparison numbers later-- old HTPC power consumption vs. new HTPC power consumption.

So I think cutting my power budget in half -- and with slightly better overall performance -- is a reasonable expectaction. That should make the HTPC trivial to cool.

[sdc]

Hi wumpus,
a few comments:

I am planning to go totally passive on the CPU heatsink.

Why going passive with the CPU, when you have several case fans, and a PSU fan which is likely to be the main source of noise? That holds especially for such a small PSU, where airflow won't be optimal.
If I were you, I would first look at modding the PSU (attaching a good fan to the outside of the case) before removing the CPU fan.

That's 70 watts for the Barton 2500+, versus ~17 watts for the Dothan 1.6ghz! (I guesstimated 1.6ghz Dothan wattage since Ralf and Intel only quote 21w for the fastest Dothan @ 2.0ghz)

I think that all Pentium M Dothans are given for 21W by Intel. According to my experience of overclocking a Dothan Celeron M, the difference is minimal (core temperature 39C at 1.4 GHz after 30 minutes Prime95, against 40C at 1.9 GHz).
However, 17W and 21W won't make a big difference anyway

[Ralf Hutter]

I'd also question the totally passive CPU cooling. A tiny bit of air, through a decently designed heatsink will cool the heck out of the P-M. An L1A or nexus 92mm at 5V will be less than 20dBA and will keep your CPU 10-20°C cooler than if you just passively cool it.

I'd also ditch the Alpha heatsink. They are good, but not under low airflow conditions. You should use a free-flowing heatsink like an XP-90, SLK900, or SP94. Any of those will cool great with a very, very low flow fan, and would probably work fine used passively, assuming the fins were oriented in the right direction.

If you're really stuck on passive CPU cooling, I'd do some research on the heatsinks that I listed, and see which of them will orient their fins in the direction of whatever case exhaust that you'll be using.

Personally, unless it just won't fit, my first choice would be the Zalman 7000, due to it's ease of mounting and excellent performance. The Zalman7000, mounted on my AOpen board, only overhangs the top edge by about 3/16". That shouldn't be any problem, unless your PSU is butted right up against your mobo.

[wumpus]

Thanks for the responses.

Does the XP-90 overhang the P4 bracket at all? I know the XP-120 does (obviously). I thought the pin-fin arrangement of the Alpha would be better in low-airflow conditions, but maybe not.

I can also duct the processor.

I plan to use the Intel EXTREME graphics 2, since this box will only be used for Windows Media Center Edition 2005 and not 3D gaming of any kind. I'm not sure how hot the NB will get, but probably negligible compared to the nForce2 Ultra with integrated GeForce 4MX I was using prior to this.

Anyway, point being, I expect the only significant source of heat in the system to be the processor at ~17w. The HDDs and NB shouldn't be generating anything close to that in wattage, and as I mentioned, no GPU.. so.. passive, plus good case airflow (eg 1 or more very low RPM system fans) seemed like the way to go.

If the CPU heat causes the PSU to ramp up, I may have to rethink this, but I'd also go with ducting before anything else.

[flyingsherpa]

with a Dothan and no vid card, your power requirements are nice and low. seems to me this would be a great time to try a power brick psu. then just use any quiet exhaust fan and you don't have to hack that noisy psu.

just my $.02

[wumpus]

I didn't even think of that, but you're right. Anyone have links handy to vendors that sell external power bricks compatible with a MicroATX mobo?

I may add something like a Radeon 9600 pro if necessary, but that'd only increase power draw by about 9w (see my exhaustive thread on that).

I'd only do that if I was forced to. I don't think Windows Media Center 2005 will have any problem running on the intel extreme 2 (particularly in light of so many OEMs who ship onboard video and default Microsoft OS installs), but we'll see.

[sthayashi]

I didn't even think of that, but you're right. Anyone have links handy to vendors that sell external power bricks compatible with a MicroATX mobo?

I know of two:
DC2DC.com (where I plan on getting my DC2DC converter package unless someone can point be to a better source)
Mini-box and go to Power Solutions

[wumpus]

Everything arrived today. I wanted to give you guys some preliminary results.

Good news: that sparkle 180w microatx psu is very quiet. I was a little worried about buying it without reading any SPCR reviews first, but it's hardly audible at all. Recommended!

I mounted the Alpha 8942 heatsink sans fan (PASSIVE), with a little ceramique. It fits great, exactly in the P4 retention bracket square. It does butt up a little against the caps; nothing a little nudge won't fix. However. I did have to remove the upper plastic washers on the four female mounting nuts to get the heatsink to "seat" on the processor. It didn't take much-- as Ralf points out in his article, there's not much height difference between a P-M and a P4 with heatspreader once you factor in the recommended tensions. It's definitely making solid contact with the die/ceramique now, and it's screwed down rather tightly. I have total confidence that most P4 heatsinks can be adapted to the P-M.

Right now I am burning in the system with Prime95 torture test. Pentium-M banias 1600mhz, vcore set to ~1.1v based on Ralf's voltage suggestion from the article. It's rock stable for over an hour.

And the best part?

As measured by my Raytek raynger st temp gun, totally passive, open air heatsink temps barely exceed 50c in an hour of Prime95! And that's with negligible airflow in this room. In any case with a reasonable amount of airflow throughput, it should do at least this well-- if not better!

And that is FRICKEN AWESOME. As far as I'm concerned, this was the best $400 I ever spent. Thanks Ralf and Mike.

For perspective, the stock Aopen northbridge cooler is running hotter (55c) than the CPU heatsink! I'm thinking of putting one of my extra Zalman coolers on that.

And btw, the Intel EXTREME graphics 2 works fine with MCE 2005. So I won't be adding an AGP card to this system. I'm glad, because I need that extra power budget for the hauppauge PCI MPEG2 encoder card that MCE requires.

[HammerSandwich]

...I just ran the kill-a-watt against an older XP 2400+ T-Bred system and got 190w at idle, and around 220w under CPU/GPU load (radeon 9600 pro).

Man, that sounds high for an XP and 9600. Sorry for the OT question, but would you detail that system's specs?

[wumpus]

Yeah, I screwed up. That's in my MAME cocktail and it includes everything on the powerstrip inside the cabinet-- eg, the creative inspire speakers/sub! So disregard that.

[wumpus]

A little update.

That sparkle 180w power supply is indeed very quiet-- with minimal load. Like so many other power supplies, the thermistor is glued flush against a heatsink inside the thing, and as soon as moderate load is put on the PS, the fan ramps dramatically. I cracked the PS and moved the thermistor far away from that heatsink so it doesn't ramp any more.

Things didn't quite go to plan; the onboard intel graphics truly don't work for actual video playback in MCE, so I was forced to use a Radeon 9600 pro instead. Still fairly modest power-wise, around 9w based on my previous testing with this card.

Here's what's in the system:

- Hauppauge 350 PCI MPEG2 encoder card
- Creative Audigy 1 PCI
- Netgear 802.11b PCI
- 256mb Radeon 9600 Pro
- Pentium-M, 1.1v, 1700mhz*
- Aopen i855 mobo
- 512 mb DDR (256mb x 2)
- three (3) 5,400 rpm 160gb samsung spinpoint HDDs
- single 60mm fan, converted to 3-pin, Zalman fanmate on minimum
- Sparkle 180w mATX PSU, thermistor moved

Kill-a-watt says..

72w at windows desktop
81w in Prime95

Assuming 65% efficiency, that means the system is actually using ~47w, and the other ~25w is lost as power supply waste heat.

The previous system had nearly identical hardware outside of the mobo. It was a nForce2 system using on-die gf4mx video, and a Barton 2500+. The power usage for that system was..

~130w at windows desktop

So, I'm pretty close to my goal halving the wattage (and hence, halving the cooling burden) of my HTPC with an actual INCREASE in overall performance! I'll have final pictures later this weekend. Here's a quick, crappy pic of the final mobo heatsink arrangement as I was bench testing the board:

http://www.wise-ebusiness.com/images/pentium-m-1.jpg

* undervolted AND overclocked. The Pentium-M is a silent PC enthusiast's wet dream.

Moderator's Edit: Linkified slightly oversized pics

[sthayashi]

Wumpus,

How do you have 3 PCI cards, a 9600 Pro, and still have it be quiet? I thought that all 9600 Pros have an active heatsink.

Or did you simply pull the plug on the fan?

[Ralf Hutter]

I thought that all 9600 Pros have an active heatsink.

I don't know what 9600Pro he's got but my Sapphire 9600Pro has a passive Zalman HS on it:

[sthayashi]

I thought that all 9600 Pros have an active heatsink.

I don't know what 9600Pro he's got but my Sapphire 9600Pro has a passive Zalman HS on it:

That thar bee an ULTIMATE 9600 Pro. Which, up until today, I thought it took space from the next PCI slot as most of the high-end passive heatsinks do.

[wumpus]

OK here are some photos.


http://www.wise-ebusiness.com/pictures/ ... pc_top.jpg

Only two fans are running in the system:

1. the thermistor/gasket modded fan in the Sparkle 180w PSU
2. one 60mm rear fan converted to 3-pin operation, on zalman fanmate set to minimum

I apologize for the ghetto mounting of the primary hard drive to the right of the DVD-R drive. It's held by sorbothane on the bottom and left sides, and a bit of ghettotastic scotch tape on the top. Eventually I want to consolidate to only TWO drives instead of THREE, if I can ever find quiet/large drives in the right size.

http://www.wise-ebusiness.com/pictures/ ... _front.jpg

Here you can see how I removed both front fans, and I stacked two spinpoints in a sorbothane "sandwich" directly behind the front air intake. They aren't really secured to anything, but the sorbothane is mighty sticky and the fit is relatively tight. They fit perfectly in that area, and should get plenty of cooling.

Which is why, again, I want to get larger QUIET drives (can someone recommend a silent 300gb or 400gb hdd?) and drop from 3 drives to 2, both in that front intake area.

The case had no feet, so I cut some small sorbothane squares to use under the 4 corners.

In case you were wondering, the system runs extremely cool even under prime95 load for extended periods fo time. The hottest area of the case is, ironically, near the hauppauge card in PCI slot 2-- that thing runs relatively hot, even with its 486 style heatsink.

The rest of the pictures can be viewed in the webserver folder.

Moderator's Edit: Linkified oversized pics

[wumpus]

Hey Ralf-- you mentioned in your review that the Pentium-M system is your main system now. Can you elaborate a little on that, eg, what's in it, some pictures, etc.

Having built a Pentium-M system, I can concur with Ralf's conclusion that the Dothan Pentium-M chip is the ideal "no compromise" silent PC build. All of the performance with none of the heat production-- albeit at a slight price premium. If anything, I think he understates the difference:

Yes, it's a powerful, low power consumption CPU, but with a little tweaking, the AMD A64 platform can cover similar ground, and costs less money. Some of us at SPCR have been begging, pleading and cajoling Intel to release a Pentium M desktop board for over a year now, and Intel still has not produced one. A year ago these P-M boards would have been compelling, but now the A64 with Cool 'n' Quiet is a serious lower cost alternative.

I suppose this depends on your definition of "can cover similar ground", because the A64 will use 40w more under load than the P-M at the same clock speed. That's a lot, especially considering the P-M is about ten percent faster than the A64 at the same clockrate.

[Ralf Hutter]

Hey Ralf-- you mentioned in your review that the Pentium-M system is your main system now. Can you elaborate a little on that, eg, what's in it, some pictures, etc.

Hardware is listed here, and it still looks like this:


I'm planning on doing some HTPC experiments before I move it into it's final home (SLK3x00), so for now it's still running in the configuration pictured above.

[wumpus]

FWIW: if, like me, you own this AOpen i855GMEm mainboard and want to use the onboard audio via SPDIF connection, you'll need this bracket adapter:

http://store.myaopen.com/aosco.html

It sucks that we have to pay $15 + shipping beyond what we already paid for this expensive mobo, just to get optical and coax SPDIF out!

But.. it's perfect for HTPC duties. I always hated having an entire PCI sound card just to output simple, basic SPDIF! With this bracket, I was able to remove the Creative Audigy from my system and use the realtek drivers (which are surprisingly good) to enable digital-only output. Works like a champ in MCE2005 and PowerDVD*, no additional hardware required.

---

* It's a long story, but MCE2005 requires a third party MPEG2 layer to play any video content at all. I know, it's insane, but that's how they designed it. PowerDVD6 is my new MPEG2 decoder of choice, since nVidia's decoders are all problematic, and WinDVD6 has weird fast forward problems within MCE.

[wumpus]

Update: A few small changes.

I dropped the Audigy in favor of the SPDIF bracket for onboard digital out. I had to buy it from the AOPEN web site for $15 as I mentioned in the previous post.

I also switched the very hot running, older model of the Hauppauge PVR-350 I had with the PVR-500 which not only runs cooler (no heatsinks on either encoder chip out of box!) but also has dual tuners. So you can record one channel while watching another, etc:

http://www.directron.com/wintvpvr500mce.html

Power usage is now at 67w idle, 76w Prime95 Torture Test. Prior to this it was at 72w/81w.

I highly recommend getting one of the newer Hauppage 500 or 150 cards for MCE tasks, they run far cooler.. consuming less than half the power of the older 350, as you can see from my example! 2x chips, less overall power consumption. Now, I'm not sure how much the Audigy contributed to that, but I'm thinking no more than 2w.

For more, here's an excellent PVR MPEG2 encoder card roundup:

http://htpcnews.com/main.php?id=pvr_card_id_guide

[tic]

I know I've seen a posting by palled saying he's using a regular XP-120 on his AOpen without problems, ... seems you wasn't able to install it on your AOpen, however?

Also.. is there any news on the Soltek 855GEI? It'll also have a Socket 478 retention bracket, cheaper and it looks like it's going to have fixed AGP/PCI locks. I know Soltek's going to announce it at CeBiT, but I'm not sure about its availability.

[wumpus]

I didn't try the XP-120 because I couldn't find any proof that it would work before I bought it.

I think the XP-120 would be, uh.. pretty kick-ass.. at cooling a ~20w load processor compared to the ~130w Prescott load it is designed for

Mostly I picked the Alpha because I thought the pin-fin design would be the most amenable to minimal airflow passive cooling.. eg lots of space between the "pins" compared to the tightly packed "fins" that ThermalRight uses.

[Green Shoes]

Great job, wumpus....you're almost to the point where you could just seal up the case and fill the whole thing up with non-conductive oil...that'd be pretty silent

[Ralf Hutter]

you're almost to the point where you could just seal up the case and fill the whole thing up with non-conductive oil...that'd be pretty silent

Hmm. this one just keeps bubbling back up to the top....

[Green Shoes]

Wow...fun stuff. So the HDD was the only thing that couldn't take the equilibrium temperature? Interesting....I might have to visit the nearest Sam's Club to see what their bulk price on baby oil is....

[sgtpokey]

wumpus, regarding storage,

I'm contemplating doing this with with my media:

http://www.buffalotech.com/products/pro ... egoryid=19

(pricey, yes but cool and not THAT pricey: $1 per gig for raw space, $1.33 per gig in Raid 5 mode)

So you just stick this puppy away somewhere and connect to it wirelessly. In order for this to be feasible, depending on your setup you may additionally have to look at some of the Pre-N wireless routers to give you enough "real-world" bandwidth, as noted in articles like this:

http://www.tomsnetworking.com/Sections-article96.php

I don't know if it'll work as your real-time live-tv drive, but it would definitely work as the long term media storage drive.

[Edwood]

I know I've seen a posting by palled saying he's using a regular XP-120 on his AOpen without problems, ... seems you wasn't able to install it on your AOpen, however?

Also.. is there any news on the Soltek 855GEI? It'll also have a Socket 478 retention bracket, cheaper and it looks like it's going to have fixed AGP/PCI locks. I know Soltek's going to announce it at CeBiT, but I'm not sure about its availability.

So what's the word? Does the XP-120 fit on the AOpen i855 GMEm or not?

-Ed

[Ralf Hutter]

So what's the word? Does the XP-120 fit on the AOpen i855 GMEm or not?

-Ed

Even if it did fit, I wouldn't use it. The XP-120 method used to clip the XP-120 onto the Intel retention bracket requires placing a lot of force on one side of the unprotected CPU die while snapping the clips into the retention bracket. A lot of force. I'd be real scared of cracking the CPU using this heatsink.

And anyway, why would you want to use it? I can't believe that it would work much better than a Zalman 7000. You can already run the Z7000 fanless, how much do you think you'd gain by using the dangerous XP-120 in it's place?

[mco_chris]

So what's the word? Does the XP-120 fit on the AOpen i855 GMEm or not?

No. I tried the XP-120 on my i855 and it does not fit. The heatsink pipes hit the retntion bracket.

The XP-90 will fit, but it hard to tell if it's making contact with the CPU die. It may be bottoming out on the rention bracket before making good contct with the CPU die.

The XP-90 is also difficult to attach - it would be easy to break the CPU die installing this heatsink. Not worth it IMHO.

[chiccoweb]

I based my system on a Dothan @ 2400 MHz, it is very powerful. I found the original DFI 855GME cooler too noisy and not so good, thus I decided to switch to CoolSystem 855 then I set up everyting inside an Antec Aria case and I fixed the case fan at 5v to reduce the noise.
The power consumption is very low so antec aria power supply is more than enough and the cooling system from Microcool is a whisper... now the less noiseless thing is the hard disk