Thermalright SI-128 CPU Cooler


CPU Coolers come in many shapes and sizes and from many sources all over the world, but only a few of the manufacturers really stand out and Thermalright is one of them. Thermalright makes some excellent quality and excellent performing products, and they have released another great addition to their CPU cooler line. Today for review I have the Thermalright SI-128 CPU Cooler and I'm impressed by what I have seen on both the Socket 939 and the LGA 775 platforms, continue reading to find out what I learned…


Thermalright SI-128 CPU Cooler

Reviewed by: Kristofer Brozio AkA Dracos

Sponsor: Thermalright


Tech Specs,Features or the Basic Info:


Thermalright SI-128 CPU Cooler



120mm fan recommended for maximum cooling capability.

Huge 8mm multiple heatpipes for even more efficient heat transfer to the aluminum fins.

Multiple tightly gapped fins for more surface area with longer and wider wingspan than SI-120.

Vast compatibility across multiple platforms for newest AMD and Intel CPUs.

Enormous wingspan gives extra cooling to MOSFET or NB chipset.

Includes adapters for LGA775, K8, and AM2 platforms

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Technical Spec.:


L125 x W145 x H91.5 mm (heatsink only)


510g (heatsink only)

Recommended Fan:

All 120mm Fan


INTEL: All Intel P4 LGA775 processors

AMD: Athlon64 / FX / X2 / Opteron all models**



A Better Look at Things



I have quite a few Thermalright products and their boxes are all pretty much the same, a plain brown box with the Thermalright logo on it. I kind of like the plain box, sometimes it doesn't have to be flashy to know what's inside, after all there is a Thermalright product inside of that box.

Lifting the lid we find separate instruction sheets for AMD and Intel installations, under those we find the SI-128 wrapped up in plastic to protect it while traveling.


Unpacking everything we find brackets for the separate installs on various platforms, a tube of thermal compound, silicon vibration dampening strips, wire clips to attach the fan and a nice Thermalright sticker.


The SI-128 is not that heavy compared to others I have used it weighs about the same as the Intel or AMD stock coolers. Being from Thermalright it is very well made and solidly constructed.



A Better Look at Things



We see four heatpipes traveling through the SI-128, they are fairly thick as well.


There are a whopping 78 fins on the SI-128, all those fins should be able to dissipate lots of heat.


All of the fins are connected together though a locking system that looks very cool and is very sturdy. Each fin has a nice silver finish on it, and the end fins have small holes for the fan clips to attach to.


The base of the SI-128 is fairly thick and features a hole in the center for the retention mechanism for all sockets.



A Better Look at Things



I've always like the industrial look and feel of Thermalright products, they look like something that will last a long time and perform well.


On the bottom we can see where all the heatpipes terminate, the base looks to be fairly smooth and flat.


Getting out my macro lens we can get a nice close up of the base, it is very smooth and flat, although there were lots of random scratches present, I can assume this happened during packing and or shipping as they seem too random to be done by machine.

If the Thermalright SI-128 is like the other Thermalright products I own then it is sure to be an excellent CPU cooler. I've always been impressed by the high quality of Thermalright products, they seem to have such high standards for product manufacturing, if only others would do the same…





Installation, Testing and Comparison

Now we get to find out what the SI-128 can do, let's jump right into the testing…


The first set of tests I used my AMD Socket 939 system with an AMD Athlon X2 4200+ CPU, I decided to test the SI-128 with a fan and without a fan to see the difference. I compared it to the Corsair Nautilus liquid cooling system and the AMD stock cooler to see how it compares. Ambient temp while testing was approximately 27C. Since the Thermalright SI-128 does not come with a fan I used a 120mm Coolermaster fan for testing with fan, it is made to be quiet, actually very quiet. (Edit: The Coolermaster 120mm fan runs at 1200RPM)


To achieve load on my X2 CPU I ran two instances of Prime95, one on each core for approximately 30 minutes and recorded the highest temps.



Thermalright (with fan): 28-29C

Thermalright (no fan): 37-38c

Corsair: 30-31c

AMD Stock: 29-30c



Thermalright (with fan): 37-38c

Thermalright (no fan): 50-51c

Corsair: 38-39c

AMD Stock: 40-41c




One thing to note is that yes it seems like the Thermalright SI-128 beats a liquid cooling system but I also have a 7800GTX and my NF4 chipset in the same loop on the Corsair Nautilus. The temps are better with just the CPU on the Corsair, but for now though we can see very good results from the Thermalright. Even with no fan the Thermalright SI-128 is very good considering that the max temp for the X2 is around 65C.



Installation, Testing and Comparison Continued:

Now for the tests on my LGA 775 setup, the CPU is a P4 Cedar Mill 631@ 3.0ghz, I did a little overclocking as well to see how the SI-128 handles some real heat. I did not do the no fan test on the Cedar mill as it runs very hot as it is and wasn't sure if I was going to fry my CPU or not, the motherboard is an ASUS P5WD2-E Premium. Stock speed is 3GHZ for this CPU, I ramped it up to 4Ghz for the overclock tests, which also meant I had to add some extra voltage and thus more heat to the mix. Not to make the testing off a bit I'm also adding Temps from my Thermaltake Rhythm water cooling kit as well.

To achieve load Prime95 was run the same as for the X2, for 35 minutes, one on each core, or virtual core, whatever the case may be…

The only temps for the 4Ghz you will see are fort he Thermalright SI-128, as the Intel stock cooler can't handle it, and we are only focusing on the SI-128 here.

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IDLE (3ghz):

Thermalright: 39-40c

TT Rhythm: 31-32c

Intel Stock: 53-54c


LOAD: (3ghz):

Thermalright: 51-52c

TT Rhythm: 48-49c

Intel Stock: 68-69c


IDLE (4ghz):

Thermalright: 46-47c


LOAD: (4ghz):

Thermalright: 62-63c



Well we can plainly see that the Thermalright SI-128 can easily handle the heat even when the CPU is overclocked by 1Ghz. The SI-128 easily blows the Intel Stock cooler away and has a decent showing against the water cooled setup as well. There were no surprises here for me, I knew that being this is a Thermalright product that the performance would be excellent and I am very happy with it. The Intel CPU Cooler is also very loud, even when not under load, so having the Thermalright SI-128 in there makes things a lot quieter and cooler.







Well as I said there were no surprises here, at least for me, I knew that the Thermalright SI-128 was going to be an excellent performer. Thermalright products are made with such a high quality manufacturing process that we can expect nothing less than perfection from them, and we get it every time it seems. The Thermalright SI-128 CPU Cooler is one of the best I have tested in quite a while, and I can easily recommend it to anyone looking for an excellent air cooling solution that is high quality and high performance.



DragonSteelMods gives the Thermalright SI-128 a 5 out of 5 score.



-Excellent quality

-Superb performance

-Works with or without fan (depending on CPU)

-Multi socket compatible


-NONE to be found!