Heatsink Compound / AMD T-bird 900

[andygold]

I recently read that there is something better than the Silicone based thermal compound (Radio Shack 276-1372)that I currently use. Anyone know exactly what this "better" stuff is, and where it can be obtained? Also, the AMD only has a tiny area that actually contacts the bottom of the heatsink. Is this the only place that the heatsink compound/thermal grease is supposed to go? Or, am I supposed to goop up the whole under side of the heatsink, and hopefully heat will tranfer through this extremely thick layer? Also, if I do lay it on thick, what about where it will hit all the surface mount devices on the CPU. Can Silicone compounds conduct current and short out these SMDs?

Thanx,

Andy

 

[MikeHelvey]

I can answer a little of your question. Just put a thin layer of grease on the core. Just enough to fill the microvoids (is that a word?) when you put the HSF on. Don't wory about putting a little too much on, it will be squeezed out. Unless you are using a metal impregnated compound, you shouldn't have to worry about it getting on anything else. . .but you want to do a neat job.

 

[Mikewarrior2]

Thick enough to fill any gaps between cpu and heatsink, but never obscenely thick.

Better Greases than RS Grease: Most other greases, ie MPU 3.7, Artic Silver, Chemtronics Silver, Melcor Aluminum nitrade, etc.

And the contact area is only that little part on the center of the chip. Apply the grease in a nice, even, fairly thin layer. Do not go too thin a layer, though, as having a little bit extra is better than having not enough.


Mike

 

[andygold]

Mikewarrior2...where can these other greases be obtained? And which is the best? Also, thanx for letting me know where to apply it...not kidding...as my previous experience has only been with nice flat, large surfaced Pentiums and K6's. Wow, it seems strange though that all the heatsinks have such a large footprint, and yet they only truly conduct at the core. IMHO, it seems like an inefficient design from a cooling standpoint. Now all I have to do is pry off the "feet" from my flipchip cooler (couldn't find any Alpha 6035's, so Alpha informed that the flipchip model 35T is identical except for the extra feet.

Thanx,

Andy

 

[Mikewarrior2]

2coolTek

CoolingStore

Millisec

The absolute best grease right now is Artic Silver. However, it is about $13 a tube(it'll last about 30 cpu applications), but you may not want to spend that much on thermal grease. I guess it depends on how much you want to spend/versus how much you want to overclock.


Mike

 

[DaddyG]

Andy,

Make sure that the clip tension is sufficient when you mod your FCPGA cooler. TBIRDS/DURONS require much higher clip pressure (AMD specs 12-20lbs) BIRDS put out a lot more heat than Pee3's, hence the higher clip pressure.

 

[andygold]

DaddyG....How does one determine the proper tension of the clip? If the heatsink doesn't move when pushed (lightly), is the tension sufficient? Not to disagree with you, but the Rep at Alpha, said that both models are identical other than the 4 pads which need to be removed. Maybe he was only speaking of the heatsink and not the clip. As I am still awaiting components to be delivered through the mail, I cannot yet determine if I'll need to bend the clip. But thanks for the heads up.

Mikewarrior2....Thanks for the leads as to the thermal grease. I agree that $13.00 is a pricey sum to pay for this item, but I spent what I consider a great sum of money on the rest of the components of the system, and I am expecting this rig to last for the next 2 or 3 years(it's very, very, very, difficult convincing the wife that I need to replace a perfectly good working unit). So, if it takes $13.00 to insure a cooler running(longer lasting, hopefully) CPU, I look at it as dollars well spent!

 

[Mikewarrior2]

i personally value artic silver as money well spent, cause it works wonders every time i have used it.


Mike

 

[Mikewarrior2]

Oh, And about DaddyG's comments.

The reason the clip needs to be tightened is because socket A chips a)sit a little bit lower than fc's and require more clip pressure than flip chips.


Mike

 

[DaddyG]

MikeW,

Think ya got it wrong, the BIRD core sits higher than the Peee3's, thats why the original ORB busted the TBIRD. The higher clip pressure is required due to the higher heat of the BIRD, about 50w from a 1 gig BIRD compared to 30 from a 1 gig Peee3. The heat causes expansion diffs in the material, that why a spring clip is required, not any kind of 'screw' mechanism. 12-20lbs pressure is spec'd by AMD but I havn't found a way to measure.

 

[Mikewarrior2]

I thought that too, in the beginning, but when I say HardOCP's picture's of the PEP66 and the gap between it(with feet on) and the t-bird 1ghz, i thoguth the t-bird sat lower.


Mike

 

[DaddyG]

Mike,

On reflection, the TBIRD core may be lower than P3 referencing the substrate, but cause of the Ceramic vs Green Fibreglass (?) the TBIRD core sits higher out of the socket.

 

[Stytis]

I heard that Artic Silver has electric conductivity that can be bad for the Processor and MoBo... does anyone know if this is true? And for Andy, just remember to put the compound on with either a razor blade or credit card so your finger oils don't get in the compound.

 

[DaddyG]

REAL Arctic Silver is not electrically cunductive. Many wanna be silvers are.

 

[Mikewarrior2]

DaddyG,

Yeah, I think you are right... I never payed attention to the thickness of the substrate. That may be higher than p3s, so i'll have to take a look later.

But My earlier reference was to the height of the core, since I wasn't thikning about rest of the chip.


Mike

 

[Tonec]

Artic Silver is conductive. Often is too low conductivity to cause any damage but do you really think that their quality control is such that certain batches wouldn't be more conductive than others.

 

[DaddyG]

Tonec,

Thats a question for Nevin, but AS is claimed to be non-conductive and I believe it.

 

[tigger80]

arctic silver is good stuff, i only get like 28C idle and 35 at full load on my system

 

[andygold]

For those that may be concerned...I included one of my other posts, and the response from Nevin...


At 07:06 AM 10/15/00, you wrote:
>>Hello,
>>I'm curious as to whether there are any bimetallic problems associated
>>with using your Artic Silver Thermal Compound in conjunction with an
>>Alpha PAL35T which is copper based, and a AMD T-bird 900. Yes, I know
>>that the 35T is designed for the Flipchips, but Alpha says it is
>>identical if I remove the 4 pads. I hope they are right.
>

No problem. The component in the suspension fluid that electrically
isolates the silver particles also helps avoid any potential bimetallic
problems.

Nevin