ThermalRight AX-7 Review
Date : Sunday, 28 July 2002
By : Stygian
Provided By : Bigfoot Computers

Introduction

My first heatsink review, which was published/posted almost a year ago, was of ThermalRight's now popular SK-6 heatsink. The design featured an all-copper heatsink with very thin fins soldered to the base, creating a relatively small-sized heatsink that performed well. ThermalRight was a fairly new name at that time, and they managed to produce a clear winner with the SK-6. However, competitors were not content with sitting around, and the likes of Alpha and Swiftech soon released their larger-sized heatsinks that could accept 80mm fans to provide better cooling to AMD CPU's, which were constantly increasing in speed and heat output. All the while, ThermalRight seemed to remain quiet despite their market adversaries moves. (ThermalRight did release several other heatsinks after the SK-6, but as far as I can tell, none of them were specifically targetted at the extreme overclocker crowd.) Enter the AX-7, the culmination of ThermalRight's efforts to create an 80mm fan-heatsink that could defeat the other 80mm fan-heatsinks out there. Can ThermalRight's AX-7 live up to the SK-6's legacy?

Specifications

To increase cooling performance and to properly accommodate an 80mm fan, the AX-7's dimensions are quite a bit different from the SK-6's. The heatsink itself is 77mm x 77mm x 42mm (L x W x H), very close in size to the Alpha PAL8045. (ThermalRight's site lists the height at 80mm, but this is with the addition of a 80mm fan that is 38mm thick, such as the Delta 68cfm fan.) The fan I used for testing (also provided by Bigfoot Computers) was the Panaflo 80mm "H1A" fan that is rated at something like 39.6cfm, and produces a liveable 32dBA of noise. No specific fan is included with the AX-7, so you can make a decision as to what level of performance/noise you want. Or, if you already have a good 80mm fan, you can save by just getting the heatsink.

The heatsink is quite heavy, at almost a pound without the fan! With the dimensions, you may also want to check if there is proper clearance around your motherboard's CPU socket for this heatsink. It can also be noted that ThermalRight was thinking not only about performance, but also about noise when they included the four rubber standoffs for placement between the fan and the heatsink. These may help cut down on the transmission of the fan's vibration to the rest of your case. The package I received from Bigfoot Computers also included a package of thermal paste, so you don't have to use the thermal pad. However, I tested all heatsinks with Arctic Silver II just to keep things the same. Like most heatsinks in its class, the AX-7 didn't come with a thermal interface already pre-installed so there was nothing to remove. Although the AX-7 doesn't look as fragile as the SK-6, it still comes packaged just as well, in a cardboard box that has inserts to ensure a snug fit for the heatsink.


What's included.
Top down view - heatsink fins protruding from centre.
Heatsink uses all six socket lugs for attachment.

The design of the AX-7 is quite different than that of the SK-6 but nonetheless is still unique. The aluminum portion features a design with fins radiating outward from the centre, providing ample surface area where there is airflow coming from the fan. There are no fins in the "dead zone" area of the fan, just below where the fan motor resides. This design or at least this concept has been featured on other heatsinks before, such as the Dr. Thermal TI-V77L heatsink I reviewed here sometime ago. The aluminum portion has then been soldered to a copper base or heat spreader that is quite thick. Only testing will tell how good this soldering job was, but if it lives up to the quality of the soldering as seen in the SK-6, I can only expect good results.


One side view.
Another side view with close-up of the clip.
Copper base.

Because of its large mass, the AX-7 uses a clip that attaches to all six lugs around the CPU socket for a secure fit and better distribution of pressure. ThermalRight chose not to go the way Alpha and Swiftech did by not utilizing the four mounting holes around the socket for direct attachment to the motherboard rather than to the socket. By doing this, they simplified installation, as it is no longer necessary to remove the motherboard for heatsink installation, whereas for the PAL8045 and MCX462 most people had to. However, this clip is otherwise not much different in that you must still use a screwdriver or other tool to apply pressure to attach the clip to the socket. No matter how many times I've done it, I still don't like having to apply that much pressure around my CPU.


Better view of base.
Aluminum heatsink is soldered to copper base/heat spreader.
The fan used for all testing: 80mm Panaflo "H1A".

The base itself is 8mm thick and has a very smooth finish, so I'd say that lapping is not needed. The side fins extend out beyond the extent of the base, allowing for air to flow straight down through them. The 80mm fan is supposed to be attached so the air blows down onto the heatsink.

Installation

Because there weren't many parts to this heatsink as compared to the PAL8045, installation was much easier. All that was required was to attach the fan to the heatsink, and then the heatsink to the motherboard. Attaching the fan to the heatsink entails threading the screws through the fan grill (optional), then through the fan, and finally through the washers. The whole thing can then be screwed onto the heatsink. You don't have to screw the fan down too tight, but the washers will be compressed a little after attachment.


Everything put together.
Washers reside between fan and heatsink.
Clip ready for attachment.

To attach the AX-7 to the socket you must first get the one side of the clip in place, which is a little tricky with a heatsink of this size. Attaching the other side of the clip requires a screwdriver as mentioned before and a sufficient amount of force. I always recommend the use of a shim for your CPU; if nothing it'll give you peace-of-mind. Don't forget to apply a fresh, thin coat of your favourite thermal paste :)
Once the clip is in place you can rest assured the AX-7 is securely mounted.


One more view.
Attached! Phew!
Crappy picture.

A much easier installation than either the PAL8045 or the MCX462 required, and you can tell by the lack of words I've had to say on this matter. No doubt, this will be one of the selling points of the AX-7 if it can perform well.

Testing

The CPU that was used was an AMD T-Bird 1.2GHz@1.33GHz with a voltage of 1.80. All the heatsinks were installed with a thin layer of Arctic Silver II thermal paste over the CPU core. Temperature readings were taken from the Asus onboard thermister using MBM, and the CPU was put at 100% utilization with the distributed.net client crunching RC5 for 1 hour. The ambient temperature was within one degree of 25C during testing. The fan used for both heatsinks was the 80mm Panaflo "H1A" pictured above. Here are the results I obtained:

As you can see, the AX-7 managed to outperform the PAL8045 with the use of the H1A 80mm Panaflo! Not a shabby job, as the PAL8045 is not a wimp of a heatsink! Things can only get better (and noisier...) with the use of higher-flow fans on this heatsink.

Conclusion

At first, I didn't know what to expect from the AX-7. Its design was quite different from the well-performing SK-6, so I had a few doubts. But after witnessing the easier-than-normal installation of this heatsink (for its size) and its killer performance, I can wholeheartedly recommend it to almost everyone out there. The clip that takes advantage of all six lugs on the socket is necessary to hold this beast in place, and it does so without making for a difficult installation. All of this, and at a price that can't be beat - under $50CDN. I can't think of any disappointments about this heatsink without being a nitpicker.

Pros

Cons

This has been one of the more pleasurable heatsinks to review, due to its ease-of-installation, and I'd like to thank Bigfoot Computers for providing the AX-7 unto me for review. Check out their site if you want to pick up an AX-7 (for under $50CDN) or something else nice for your computer. Thanks for reading this review, and feel free to e-mail me your comments.

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