Corsair A70 Heatsink Review

After reviewing the H50 and H70 low cost liquid cooling solutions that Corsair is selling, I became curious about how well their other cooling solutions perform. Besides the above mentioned units, Corsair is also selling the A50 and A70 tower style heat sinks. The A50 seems to be budgeted at the lower end of the premium cooling scene and the A70 looks like it is being marketed more at the high end scene, in competition with the likes of Thermalright, Prolimatech and Noctua. Since Corsair didn’t bother sending either one of these for review, I got kind of curious to see if they were trying to hide behind the performance of their H50 and H70 solutions and went ahead and bought an A70 to review and see if it works well or if Corsair has something to hide with their conventional heat sink offerings.

Specifications (Courtesy Corsair)

Features

• Compatible with Intel and AMD systems
• Four 8 mm copper direct-contact heatpipes
• Aluminum fins
• Low-noise, low-vibration 120 mm fans mounted on rubber studs
• Selectable 1,600 or 2,000 RPM allows you to select the cooling performance you want
• Two-year warranty

Specifications

• Model CAFCA70
• Heatsink dimensions 159.5 mm x 124.6 mm x 129 mm
• Fan Dimensions 120 mm x 25 mm
• Fan speed Selectable 1,600 or 2,000 RPM
• Air flow 50 – 61 CFM
• Static pressure 1.8 – 2.3 mm H2O
• Noise level 26 – 31.5 dBA

Compatibility

Includes mounting brackets for Intel LGA775, Intel LGA1366, Intel LGA 1156, AMD socket AM2 and AMD socket AM3 motherboards.

The fan/cooling fin structure is elevated 43 mm (1.69”) from the motherboard. Some motherboards outfitted with six pieces (6 GB or 12 GB) of RAM with tall heat spreaders, such as Corsair Dominator and Dominator GT, may not provide enough clearance between the CPU and the closest memory slot. Motherboards with standard height memory do not present a potential compatibility issue.

Packaging

The box the H70 comes in is sized at 262 mm X 210 mm X 132 mm. The box is sturdily constructed and uses foam extensively around the heat sink itself. The mounting hardware comes inside a separate cardboard box inside the shipping box, as do the fan/mount assemblies. All in all, a very secure shipping solution. Below are some pictures of the box and heat sink.

The heat sink itself has a mass of 693.5 grams with the Intel “H” mounting plate installed on the heat sink, as measured on an Ohaus 2610 triple beam balance. The base is of the direct touch heatpipe style, with 4 heatpipes being evenly distributed across the bottom of the mounting base. Checking with my metal ruler, the base is about as flat as you can make an HDT style base. Also included with this heat sink is a very brief Quick Installation booklet; more on that later. The fan/mount assemblies included with this heat sink have a mass of 134.7 grams and clip onto the end of the heat sink itself. When I first looked at the mounts I thought they would be flimsy, but in use I found them to hold securely, even with much heavier fans installed on them.

Installation

The included Quick Install guide is pretty bad, as far as installing on Intel systems go. Corsair doesn’t help matters on their website either, as you have to look in their forums to even find a link to the .pdf file on installing this heat sink. This still doesn’t cover a few parts on the mounting hardware included with the kit either. For AMD systems, the mount is much simpler since it uses the stock AMD retention module and with the way it clamps the heat sink, this can be used with the older AMD Athlon64 and Opteron sockets such as socket 939 and even socket 754 systems.

For mounting on Intel LGA 1366 and LGA 775 systems (and LGA 1156 too, though I don’t own one), I found the following to be the best method for mounting. For either LGA 1366 and LGA 1156, which both come with a back plate under the socket, there are 4 black plastic washers included with the mounting hardware that need to go on the four mounting posts before pushing them through the holes on the motherboard. They act as spacers to compensate for the thickness of the Intel mandated backplate under the motherboard and keep the mounting posts from bending the Corsair backplate when the heat sink is mounted. For LGA775 systems, which don’t have the Intel-mandated back plate under the socket, the 4 black plastic spacers are not needed to correctly mount the heat sink. After testing this heat sink on my test system, I mounted this heat sink on a LGA775 system to verify this information. Also, a bit different with the more normal Intel mounts used with other premium heat sinks, this one has an “H” bracket that screws to the base and it also doesn’t use springs, but rather depends on the torsion of the “H” bracket for tension.

Once I figured out the correct mounting procedure, it made for a very secure and repeatable mount, with little variation in temps between mounts. One other point I want to bring up that is incorrect on Corsair’s mounting guide for both AMD and Intel is the way they suggest to apply the TIM. Their guide shows using the “pea sized drop in the middle of the IHS” method, which doesn’t work well with HDT type heatsinks. Rather, I applied a thin line down each heatpipe instead, which gave me better temps. I compared the two methods of application and found the pea sized application in the middle of the IHS to give 4 °C worse temps as compared to the line method. Also, on the two outer heatpipes, put the line of TIM to the inside of those two heatpipes as those don’t sit all the way on the IHS on my LGA1366 processor. One final note about installation: this heat sink is asymmetrical in design and has a definite front and a back side to it. The bowed side needs to face the ram slots as it gives more clearance between the fan and the ram slots.

Test Setup

Fans used for testing were as follows:

I’ve added the Delta fans to my testing since I got them at a good price and represent a more moderate cost cooling solution in the extreme realm than the Sanyo Denki compound fan. The noise from a pair of these is much more tolerable than the Sanyo Denki, with not nearly as much motor whine from them. They are not quiet by any means, but the noise from them is more flow noise than motor whine and blade pop like the Denki.

The testbed system consists of the following components:

• Case – Chieftech clone of the Antec 1040 case series, with the original 80 mm exhaust fans being removed and the holes enlarged to mount two 92 mm fans externally on the outside of the rear case bulkhead instead of internally.
• Motherboard – Asus P6T
• Processor – Intel Core i7 Extreme 980X, overclocked to 4000 MHz @ 1.304 v.
• RAM – Corsair XMS3 DDR3 1600
• Video Card – eVGA 7900GTX
• Power Supply – HEC Cougar series (German HEC, not US model) S700
• Hard Drive – Western Digital Caviar 250 GB SATA hard drive
• Optical Drive – Lite On DVD-RW drive
• OS – Windows Vista Ultimate 64 Service Pack 2
• Arctic Cooling MX2 thermal paste was used for testing as I have found it to give good consistent results with no appreciable break in and it applies and cleans up easily.

Test Methodology and Results

The testing methodology used is the same as I used with my previous reviews. All energy saving features of the motherboard and processor were turned off to keep it from down clocking the processor speed and vcore. All fan control functions were turned off in bios to keep the fans at maximum speed. For processor temperature monitoring purposes, I am using Real Temp 3.40, with logging enabled at 2 second intervals.

Temps in my computer room were maintained between 20.5 to 21.1 °C (69-70 °F), measured at the front of the case. If room temperatures exceeded these parameters I re-ran that individual test run.

For loading the CPU, I used Prime95 version 25.8 using in-place large FFT’s and ran it for 30 minutes to stabilize temps. After 30 minutes, I would exit Prime95 and let the CPU idle for at least 10 minutes. The highest recorded temperature from the hottest core for each run was then recorded off of the Real Temp log, the lowest temperature on any core was recorded and the average temperature on the hottest core was calculated during the load portion of each run.

Each fan configuration was tested with three remounts of the heat sink, and the lowest average temperature run recorded, to minimize any problems between mount to mount installations. When testing in the extreme performance realm with the SanAce 9CR1212P0G03, it was installed in a push configuration, just like my tests with it on the other premium heat sinks I’ve tested.

This first chart gives the results with the various fan combinations I tested:

The first thing I noticed is that this design doesn’t scale well with higher CFM and static pressure fans. It really didn’t start showing a noticeable gain in performance until the extreme performance fans were installed on the heat sink. The 120 X 38 mm Panaflo L1BX fan actually performed worse than the stock fans from Corsair, which was a big surprise to me too. Most people won’t want to live with the noise of a pair of focused flow Delta fans or that Sanyo Denki Beast fan for everyday usage, so Corsair did a good job of choosing the fans for this heatsink that maximize cooling without getting too noisy. For comparing the performance of the A70 to other heat sinks that come as an out-of-the-box cooling solution I have tested, we have the following table to look at.

Conclusion

As you can see, the performance of the A70 is in the ballpark with other high end cooling options. It matches the True Spirit and beats the H50 in cooling, but lags behind the rest by a little. All in all, a pretty good showing for a heat sink that is nowhere near the top in the cost column. The A70 does have a few drawbacks, in that it will not play well with RAM that uses tall heatspreaders and its design will pretty much cover the first RAM slot on most motherboards. Their installation directions leave much to be desired. It also has several items in the plus column, in that it performs well as delivered and the Intel mounting system holds very securely and isn’t too hard to put on inside the case. The A70 is a good performing heat sink and is worthy of consideration when you are deciding on your next cooling solution to buy. As such, I give this heat sink the Overclockers Approved award.

– muddocktor