Questions from an AMD Video

[wjperry]

I am about to seat the CPU, heatsink and fan on yet a fourth build. I have always used Artic Silver 5. Even replacing any thermal pads on stock heat sinks with AS5. I ran across an interesting AMD sponsored video that is posted on Newegg. It is entitled “Thermal Pad or Paste?”. My surprise was that AMD didn’t totally eliminate the paste as an option. In fact they indicate it should be used where the heatsink is likely to be removed and replaced multiple times, such as a testing environment. Their spin on pads is that they should be used in a long-run, production environment since pads will not disperse with time.

I have not been at this long enough to have any opinion but I know many of you have. Is AS5 going to hold up for say two years? Anyone have long term experience using AS5 or the pads to tell any difference?

[doctorgonzo]

I think they are exaggerating a bit when they say that thermal grease won't last long. While there is a chance that over a long period of time the grease may dry out, two years isn't a long period of time.

[wjperry]

doctorgonzo,
Thanks for the response. I thought there would have been a few more willing to offer up an opinion. I'm like you, I suspect it is a bit of a stretch. Remember, the two years is my figure, not theirs. I feel compelled to continue using AS5 & remove the pad from this stock Heatsink.

[Panama Red]

Originally Posted by wjperry I feel compelled to continue using AS5 & remove the pad from this stock Heatsink.

While this practice may provide a better heat transfer, it's my understanding that installing a heat sink on a retail version cpu without the factory provided thermal pad will void the warranty. Also consider that Arctic Silver says on their site that AS5 needs to "cure" for at least 200 hours before the best transfer is achieved.

[wjperry]

Panama Red,
I agree about the voiding of the warranty. That is exactly why it surprised me that AMD would even mention the use of a paste. If I were in their shoes I would probably say "don't do it".
The 200 hours is about a month of eight hour days. I don't know that that statistic gives anyone any comfort!

[Panama Red]

I don't think the 200 hours means it doens't work well until the 200 hours is up. It just improves over that time. Right out of the tube, AS5 is superior to factory thermal pads. I've personally documented that on a couple of overclocking rigs.

[wjperry]

Outstanding!! That is what I wanted to hear from someone. Coming from you it means a lot! AS5, here I come!!!!

[Cricket]

As to the longevity of Arctic Silver...lately I've been having to look at computers I built 3 to 4 years ago and when pulling the heatsink find that the Arctic Silver II I applied is still moist and rubs off easily. I've seen cheaper white thermal compounds become dry and hard after just a few years of use but Arctic Silver seems to stand up pretty well over time.

Cricket

[TwoRails]

Technologically, using "grease" on either AMD or Intel retail CPUs will void the warranty. I poked around in the AMD forums and found some "unofficial" info. With the old XP style, and the like, it would void the warranty because you could short out the CPU. From reading the forums, though, grease on a CPU with a spreader, like the 939s, Opterons, etc., does not void the warranty as nothing can short out. Remember, though, this is unofficial....

Not being an OCer, I haven't messed with "fancy" HS/fan combos in years. Back then, "squeeze-out" did seem to exist. Trying out copper based HSs using early versions of AS, temps did seem to climb up a little after use. I'm sure things have changed greatly over the years, however. Since I personally can't justify the minor drop in temps versus cost, I've stayed with the PIB (retail) units to have the 3 year warranty over 30 days.

[wjperry]

Thanks for all the posts. I think I'll stick with the AS5. So far so good!

[glc]

Actually, what you should do to preserve warranty if you remove the stock cooling solution is use material on AMD's "approved" list - and no Arctic Silver products are on that list.

What type of thermal interface material should I use with my AMD Athlon™ 64 processor?





Thermal Interface Materials for AMD Opteron™ and AMD Athlon™ 64 Processors



AMD evaluates thermal interface materials for use with its AMD Opteron™ and AMD Athlon™ 64 processors. A list of suggested materials is provided in the table below.
Suggested Thermal Interface Materials
Manufacturer Interface Material Material Type
Bergquist TIC-3000 Grease
Shin Etsu G751 Grease
Shin Etsu X23-7762 Grease
Shin Etsu X23-7783D Grease
Thermoset, Lord CPD TC-350 Grease

The heatsink makes contact with the top surface of the processor package utilizing the thermal interface material between the processor lid and the heatsink. AMD recommends using a high-performance grease such as those listed in the table above. AMD does not recommend using phase-change materials between the heatsink and the processor.

Phase-change materials develop high adhesion forces between the heatsink and processor when the material is in the solid phase. This strong adhesive force may cause the processor to stick to the heatsink. During heatsink removal, this strong adhesive force may cause the processor to be removed from the socket while it is locked, and this action may result in damage to the socket or to the processor pins.

Most grease should be applied in a 34 - 35 mm square that is 0.06 - 0.08 mm thick. This amount of grease has provided good coverage of the processor lid while not being excessive. If excessive amounts are applied, grease may flow over the edges of the processor and reach the socket . This is not desirable.

What type of thermal interface material should I use with a Socket A processor?





Recommended Thermal Interface Material



When installing a heatsink on a Socket A AMD Athlon™ or AMD Duron™ processor, thermal interface material must be used. Thermal interface material helps conduct heat from the processor to the heatsink, where it can be effectively dissipated. Phase Change Material (PCM) is the recommended interface material for Socket A AMD Athlon and AMD Duron processors. Many heatsinks are sold with a pre-applied phase change material interface.

Phase change material is different from Thermal Tape or Thermal Grease, neither of which is recommended by AMD for use with AMD Athlon or AMD Duron processors. Care should be taken so as not to confuse thermal greases or tapes with PCM. Phase change material is usually similar in color and consistency to bubble gum or silly putty, and will initially be covered by a plastic film to protect it until use. Once heated, it will change state and adhere to the processor. Once the material changes state, the heatsink should not be removed. If the heatsink is removed, any remaining phase change material will need to be removed and a new thermal interface applied before re-installing the heatsink.

A list of suggested materials evaluated by AMD is provided in the table below. For purchasing information, contact the manufacturer for a list of their distributors/vendors.
Manufacturer Product
Bergquist HF225UT
Chomerics T725
Honeywell PCM45
Power Devices Powerfilm
ShinEtsu PCS-TC-11T-13
Thermagon T-pcm905C



For additional information on thermal solutions for Socket A processors, download the AMD Thermal, Mechanical, and Chassis Cooling Design Guide from the AMD Athlon™ XP Processor Tech Docs page.