Xigmatek HDT-S1283 & SD964 “heatpipe direct-touch” CPU coolers

Table of Contents

Yes, these tower coolers from Xigmatek feature bases in which the heatpipes themselves make direct contact with the top of the CPU. Elimination of a heat transfer interface to improve cooling performance is the aim. In other aspects, the coolers are typical heatpipe tower coolers. Does it work?

April 3, 2008 by Lawrence
with Mike Chin

Xigmatek HDT-S1283
CPU Cooler
Xigmatek HDT-SD964
CPU Cooler
Street Price
~$35 USD ~$30 USD

There seems to be one constant when it comes to CPU coolers — they keep getting larger and larger. And for good reason — usually in
head-to-head competition, the bigger heatsink prevails. Our current
champion, the Thermalright Ultra-120 Extreme is a prime example. Not only is
it very wide and tall, it’s not exactly a featherweight, either. The Extreme
weighs 790g, without a fan, and a typical 120mm fan weighs 150g. Having almost
one kilogram hanging sideways off a motherboard mounted in a tower case isn’t
easy on the nerves. The extra amount of material required to manufacture such
a behemoth also makes the overall cost high.

While tower heatsinks have become larger, the efficiency has not really changed
as manufacturers stick to the same common design: Heatpipes soldered to
a copper base and multiple aluminum fins rising up
to as high as 16cm. The majority of the heat generated by a CPU has to go through
several mediums: The CPU heatspreader, the base of the heatsink,
the heatpipes, the fins, and from the fins, finally, to the air. Each transition represents an impedance point for heat transfer.

The Xigmatek HDT-S1283 and HDT-SD964 coolers tweak this model by eliminating
one of the middle-men in the heat transfer chain: The base. Flattened heatpipes
form their own base and make direct contact with the CPU heatspreader, thus eliminating the usual copper plate which forms the base.
Both heatsinks are also fairly light by modern standards, weighing closer to
a pound than a kilogram. The S1283 appears to be a standard tower heatsink with
three heatpipes and is designed to be used with a 120mm fan. The shorter SD964
has much less surface area, though it does sport an extra heatpipe. It is paired
with a 92mm fan.

Xigmatek appears to make and sell these products to other brands. For example, the Kingwin Revolution is identical to Xigmatek’s HDT-963, and the OCZ Vendetta is also very similar. OCZ’s promotional material about the Vendetta states, "Using a distinctive, highly efficient heat pipe and fin design developed by Xigmatek…" which makes it clear that Xigmatek is the manufacturer.

Xigmatek’s retail boxes are not excessive compared to many others.

Xigmatek HDT-S1283 and SD964: Key Features
the respective product web pages here
and here)
Feature & Brief
Our Comment
H.D.T. (Heat-pipe direct
touch) technology.
Eliminating one
heat transfer interface will likely improve performance.

Anti-vibration rubber design.

Good. They can reduce vibration transmission, provided
they do not create a wide separation between the fan and heatsink.
Option of Double fans installed
(SD964 only)
The SD964 with only a
92mm fan, may benefit from a push-pull setup.

Particular spoiler design.
(S1283 only)

The spoiler is intended
to direct airflow toward some of the board components.
3pcs high performance U
type heat-pipe.
(4pcs for SD964)
Typical of today’s tower
Light weight. The lack of bulk means
they will have to be very efficient to compete with the big boys.
High performance &
easy installation.
To be determined.
120mm highly efficient
PWM fan (92mm for SD964)
PWM fans are useful as some motherboards do not support DC voltage control.
3 in 1 application: LGA775
push-pin/K8 & AM2 tool-less clip.
No love for S478.
Xigmatek HDT-S1283 and HDT-SD964: Specifications
(from the respective product web pages here
and here)
Product Name
Product Number
120(W) x 50(H) x 159(D) mm
92(W) x 51(H) x 133(D) mm
600g (w/fan)
466g (w/fan)
Thermal Resistance


All Intel Socket 775 CPU
Core 2 Extreme / Quad / Duo
Pentium Extreme Edition / D
Celeron D

All AMD Socket AM2 / 754 / 939 / 940 CPU
Athlon 64 / FX / X2 / Opteron / Sempron

Copper base, Aluminum Alloy fins
8mm x 3
6mm x 4

120(W) x 120(H) x 25(D) mm

92(W) x 92(H) x 25(D) mm
Voltage Rating
800~1500 R.P.M.
1200~2800 R.P.M.
Bearing Type
Rifle Bearing
Air Flow
56.3 CFM
39~54.6 CFM
Air Pressure
1.57 mmH2O
1.7~3.3 mmH2O
Life Expectance
40,000 hrs
50,000 hrs
Noise Level
27.2 dBA
22~30 dBA
4 Pin with PWM


Included in the retail box is the heatsink, a 120x25mm PWM fan,
4-pin molex fan adapter, thermal compound, mounting hardware, and a
user manual. The SD964 comes with the same accessories.

At first glance, the HDT-S1283 appears to be just another tower heatsink,
albeit a very lanky one.

Compared to the Thermalright Ultra-120 Extreme, it is about the same
height (the LGA775 push-pins prop the S1283 up a bit in the above picture), but is half an
inch shorter in both length and width.

The base.

The most interesting feature is the heatsink’s base. The 8mm thick heatpipes
are flattened at the bottom to make direct contact (or "touch" as
Xigmatek likes to refer to it). Though it was slightly tarnished and there
were some light machine marks, the base was very flat.

The grooved plate
which hold the heatpipes is not really designed to aid heat transfer. It may be made from cast aluminum. It’s not clear whether the heatpipes are just press-fitted into the grooved plate or soldered. Performance might have been improved slightly by making this plate from copper
and soldering it to the heatpipes.

A "spoiler" to deflect some of the airflow can be clipped on a fin at any point on the side opposite the fan. It does not extend the entire width of the
heatsink, making its usefulness somewhat limited… like most car


The fan only draws 1.56W at 12V. A cursory Google search of the model
number associated it with a variant of Arctic Cooling’s AF12025PWM fan.
However Arctic Cooling’s fans use fluid dynamic bearings, not rifle bearings.

The included fan isolators are designed with a slit to fit through one
of the heatsink’s fins, and are barrel-shaped at the ends so they will
fit in a long groove running down each side of the heatsink.

The method by which the fan isolators are attached is quite sound —
fairly easy to use and stable.

The K8/AM2 mounting clip

For AMD systems, a simple tension clip is provided to attach
the heatsink to the stock mounting mechanism. The clip can only be used in one orientation. On most
AM2 socket motherboards in a typical ATX case, the fan will end up blowing toward the power supply
than toward the rear exhaust.

The LGA775 mounting frame.

For use on a LGA775 platform, the dreaded standard Intel push-pin
mechanism is implemented via a pair of mounting arms which screw onto the base
plate. Normally we don’t like to see push-pins
on large heatsinks like the
Scythe Ninja, but in this case, the heatsink’s low weight makes it more

Heatsink mounted on our test platform with our reference Nexus fan.

Though the user manual recommends attaching the isolators
to the fan first and then slipping the fan on horizontally, we found this
method to be very difficult. We recommend placing the isolators on the heatsink
first, and pulling them through the holes on the fan using pliers (twirling
them around the pliers helps as there is not a lot of room to work with).
Note, if you place the fan on first, it overhangs two of the push-pins.
It may be difficult to get enough leverage to engage them properly.

Getting the pins to lock on to the motherboard was a bit awkward on the fan side, as push-pins are partially obscured by the fan, but no tools were required. It’s definitely easier to mount the heatsink with the motherboard not installed in a case. Once the heatsink was secured, the bowing of the board around the CPU socket made it clear that there’s quite a bit of tension applied between the base and the CPU. Inadequate pressure is not likely to be a problem here unless you mount the pins improperly.


The SD964 is dwarfed by the S1283 and Thermalright Ultra-120 Extreme.
Compared to its big brother, the SD964 is shorter by about an inch in
both height and length. It utilizes 4 x 6mm heatpipes rather than 3 x

Its dimensions are not unusual for a 92mm tower heatsink — it’s very similar in size to the Noctua NH-U9 on the right.

A Google search of the fan’s model number reveals it to be the same as
the one included with the OCZ Vendetta according to Frostytech.
At 12V, it draws 3.6W of power.

The installation procedure is identical to the S1283. Notice the grooves
on both sides of the SD964, allowing one to install a second fan if so

The installation procedure with the SD964 was essentially identical to that of the S1283. Due to the smaller fan diamater, the pushpins are more accessible and are thus easier to secure. In most systems, installation of this heatsink with the motherboard already installed in the case will probably post no great challenge.


Testing was done according to our
unique heatsink testing methodology
, and the reference fan was profiled
using our standard fan testing
. A quick summary of the components, tools, and procedures
follows below.

Key Components in Heatsink Test Platform:

  • Intel
    Pentium D 950
    Presler core. TDP of 130W; under our test load, it measures
    78W including efficiency losses in the VRMs.
  • ASUS
    motherboard. A basic microATX board with integrated graphics
    and plenty of room around the CPU socket.
  • Samsung
    40GB 2.5" notebook drive
  • 1
    GB stick of Corsair XMS2
    DDR2 memory.
  • FSP
    300W fanless power supply.
  • Arctic
    Lumière: Special fast-curing thermal interface
    material, designed specifically for test labs.

Test Tools

  • Seasonic
    Power Angel
    for measuring AC power at the wall to ensure that the
    heat output remains consistent.
  • Custom-built, four-channel variable DC power supply,
    used to regulate the fan speed during the test.
  • Bruel & Kjaer (B&K) model 2203 Sound Level
    . Used to accurately measure noise down to 20 dBA and below.
  • Various other tools for testing fans, as documented
    in our standard fan testing

Software Tools

  • SpeedFan
    , used to monitor the on-chip thermal sensor. This sensor is not
    calibrated, so results are not universally applicable
  • CPUBurn
    , used to stress the CPU heavily, generating more heat than most
    real applications. Two instances are used to ensure that both cores are stressed.
  • Throttlewatch
    , used to monitor the throttling feature of the CPU to determine
    when overheating occurs.

Noise measurements were made with the fan powered from the lab’s variable DC
power supply while the rest of the system was off to ensure that system noise
did not skew the measurements.

Load testing was accomplished using CPUBurn to stress
the processor, and the graph function in SpeedFan was used to make sure that
the load temperature was stable for at least ten minutes. The stock fan was
tested at various voltages to represent a good cross-section of its airflow
and noise performance.

The ambient conditions during testing were 18 dBA and


Stock HDT-S1283 Fan

The stock fan was tested for acoustics. We didn’t do a full range of airflow
/ noise tests, but SPL and RPM measurements were taken at 9V, 10V, 11V, and
12V. Normally we test at 5V, 7V, 9V, and 12V, but at 7V the stock fan barely
spun at all (less than 100 RPM). Also, the fan would not start up with less
than 8.7V, so 9V seemed like a good starting point. The non-linear relationship between voltage and RPM reflects this fan’s PWM design. A PWM fan controller would
probably be better for this fan. Most of the fan controllers built into motherboards these days are PWM, so they may work well. However, implementation of PWM fan control varies widely from board to board.

HDT-S1283 Stock Fan Measurements
Fan Voltage
Fan Speed
Noise Level
1400 RPM
28 dBA@1m
1230 RPM
25 dBA@1m
960 RPM
21 dBA@1m
670 RPM
19 dBA@1m

At 12V, there was a lot of turbulence. Not suitable for a silent PC, but
much better than most stock fans that pass through the lab. At 11V it was
bearable, but still not good enough by our standards. At 10V it really ramped
down quite a bit and became fairly quiet. 9V was barely audible above the
ambient noise level. Inside a typical, enclosed system, it would probably
be indiscernable from the rest of the system noise.

The noise characteristics were fairly benign. At 1m there is a slight buzz
and a sound reminiscent of something brushing up against a polyester sleeve.
At higher fan speeds (higher than 10V), the extra turbulence dominates the
noise profile. Overall, it’s very similar to a typical high/medium speed sleeve
bearing fan.

Cooling Results

w/ stock fan
Fan Voltage
Noise @1m
°C Rise
28 dBA
25 dBA
21 dBA
19 dBA
HDT-S1283 w/ reference fan
22 dBA
~19 dBA
<19 dBA
<19 dBA
Load Temp: CPUBurn for ~10 mins.
°C Rise: Temperature rise above ambient (21°C) at load.
°C/W: based on the amount of heat dissipated by the CPU (measured
78W); lower is better.

The heatsink in conjunction with the stock fan provided excellent cooling at
each fan voltage we tested. At 12V and 11V the increase in temperature was superb, among the lowest we’ve ever encountered. Performance did not suffer significantly
at 10V or 9V. We never would’ve expected such great results from such a light-weight

Already impressed, we put on the reference fan and re-tested the heatsink.
Amazingly at 12V, our reference Nexus 120mm fan achieved the same result as
the stock fan but with a 6 dBA improvement in noise level. High airflow does
not seem to affect performance drastically. As the fan voltage was lowered,
the increase in cooling efficiency tapered off, however at 5V, the rise in
temperature was only 22°C over ambient — the best result we’ve ever

HDT-S1283 vs. Top Competitors w/ reference fan
Noise @1m
Thermal Performance (°C
Ultra-120 Extreme
Ninja Copper
22 dBA
~19 dBA
<19 dBA
<19 dBA

Compared to the other elite CPU coolers we’ve tested in the past, the HDT-S1283
comes in a close second to the Thermalright Ultra-120 Extreme. A measured
difference of one degree is not enough to call one heatsink better than the
other however. It was also the best performing heatsink we’ve tested with
the Nexus fan at 5V (along with the Scythe Ninja Copper), though the tight
fin spacing makes it a poor choice for completely passive operation.


Stock HDT-SD964 Fan

The stock fan was tested for acoustics. We didn’t do
a full range of airflow / noise tests, but SPL and RPM measurements were taken
at 8V, 9V, and 12V. As with the 120mm fan on the bigger heatsink, this one is also a PWM fan, and subject to the same voltage/speed non-linearity.

HDT-SD964 Stock Fan Measurements
Fan Voltage
Fan Speed
Noise Level
2750 RPM
40 dBA@1m
1230 RPM
21 dBA@1m
600 RPM
18 dBA@1m

Cooling Results

w/ stock fan
Fan Voltage
Noise @1m
°C Rise
40 dBA
21 dBA
18 dBA
HDT-SD964 w/
reference fan
21 dBA
19 dBA
<18 dBA
Load Temp: CPUBurn for ~10 mins.
°C Rise: Temperature rise above ambient (21°C) at load.
°C/W: based on the amount of heat dissipated by the CPU (measured
78W); lower is better.

The SD964, as one would expect with its smaller size and 92mm fan,
could not match the S1283’s performance. It did an excellent
job with the stock fan at 12V, but it was too noisy. At 9V, at less than half the full speed, it was much quieter
but still performed very well. This is probably the optimal balance between noise and cooling performance for most silent PC enthusiasts with this HSF. A temperature rise at load of just 20°C is good enough for any system. The result at 8V indicates that the airflow had dipped too low.

The performance with the reference 92mm fan at 9V was excellent, as the noise level here is below the the ambient in most environments. A temperature rise of 26°C is certainly good enough to keep our test CPU under 60°C in any decently configured case. Even the 7V performance is probably good enough, and utterly inaudible in any real application.

HDT-SD964: Comparables
Fan Voltage
Ninja Mini w/ 80mm reference fan
HDT-SD964 w/ 92mm reference fan
SI-128 w/ 120mm reference fan
°C Rise
°C Rise
°C Rise
20 dBA
21 dBA
22 dBA
~19 dBA
19 dBA
~19 dBA
<18 dBA
<18 dBA
<19 dBA

Going through the archives of previously reviewed heatsinks, we found two
coolers that matched up to the SD964’s performance: the Scythe Ninja Mini,
and the Thermalright SI-128. The results were very close amongst the three
at similar noise levels, despite the fact that the Ninja
Mini and SI-128 were tested with an 80mm and a 120mm fan, respectively. The SD964’s performance is just about
where it should be — equivalent to an excellent 80mm fan cooler or a
dated 120mm fan cooler.


As far as value goes, the Xigmatek HDT-S1283 is in a league of its own.
It basically matched the performance of our current champion, the Thermalright Ultra-120
Extreme, even though it is smaller in every dimension, significantly lighter,
and has a considerably lower price. It seems evident that the heatpipe direct-touch
"technology" does indeed work, as the rest of the heatsink’s design
is not noticeably different from its competitors.

The HDT-SD964 is also a good performer, matching the best similar sized coolers tested in the past.
If mass is an issue, it’s an excellent choice. If it isn’t, the
Scythe Ninja Mini may be a better option. The Minja achieved equal performance,
but with an 80mm fan, and it is shorter, making it more compatible
with low profile cases.

The LGA775 stock mounting system is perfectly sufficient for the SD964,
but it’s not ideal for the S1283 due to its higher weight. This is
probably not a big issue, however, the total mass with fan of 600g is quite modest, relatively speaking. It exceeds Intel’s recommended 450g maximum for the 775 socket by only 150g.

With either heatsink on most AM2 motherboards, the one-way mounting clip will cause the fan into a
position where it blows toward the power supply (in the typical ATX case). It means that instead of being blown mostly out the back by the case fan, the heated air from the CPU heatsink will be blown more into the PSU, which may cause its thermally-controlled fan to speed up and become noisy.
Some way of allowing 90° rotation in the mounting orientation of the heatsink would be much preferred.

The stock fans that come with the Xigmatek coolers are not optimized for minimal noise. At the standard 12V, they simply spin too fast
for our liking. On the other hand, overclockers and gamers in the DIY PC community expect to be able to reach maximum cooling performance, and a high speed fan is part and parcel of the maximum-performance-at-any-cost credo. Our testing showed that the S1283 fan did almost as well at
960 RPM as it did at its maximum 1400 RPM: There was only a 3°C
hit in performance, but the noise level dropped from plainly audible down to near ambient. The SD964 fan
was very loud at its maximum speed.
While it will undoubtedly be judged better by review sites that deemphasize noise, 40 dBA at 1m, to us, is downright offensive. No one today expects a 92mm
heatsink to provide penultimate cooling — they really should dial it down
a notch or two.

Overall, the Xigmatek HDT-S1283 and HDT-S964 represent good value in high performance coolers that can be run very quietly. We recommend them with only a few caveats.

Xigmatek HDT-S1283

* Champion-level cooling peformance
* Light-weight
* Anti-vibration fan isolators
* Low price


* Stock fan is louder than necessary
* Can mount on AMD platforms in only one orientation
* LGA775 mounting could be improved

Xigmatek HDT-SD964

* Good cooling proficiency
* Anti-vibration fan isolators
* Weighs only 1lb w/ fan, within Intel and AMD spec for coolers


* Stock fan is much louder than necessary
* Can mount on AMD platforms in only one orientation

Our thanks to Xigmatek
for the heatsink samples.

* * *

Articles of Related Interest
Ninja Copper: Scythe’s 5th
Year Celebration

Thermalright Ultra-120 eXtreme:
Heir to the CPU Cooling Throne

Scythe Ninja Mini CPU heatsink
Thermalright SI-128: Evolution of a Past Master


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