Topic: 5970 new thermal pads (Read 3605 times)

I know this is an old thread, but I used the same exact thermal pads in the same exact configuration (0.5mm on everything except the PCI-E bridge chip and the big blocky chips next the the hot VRM's) and my results are pretty much spot on with what you said. The pads are amazing, though a little tricky to work with.

What you said about using thick thermal paste I believe is wrong though. You want the heatsink and the hot gpu core to be as close as possible. If it's clogged with a lot of low thermal conductive thermal paste (compared to solid copper), the heat won't dissipate as good. If you apply your paste good enough, using "thin" paste will work just as well; just don't shift the heatsink around when sandwiching it all together. Having excessive paste ooze out the sides of the GPU core is fine as long as there is great contact between the entire GPU die and the copper heatsink that is on top of it. If none oozes out, you could be left with gaps between the heatsink and core, which means less surface area to allow for the heat to transfer into the heatsink.

I own 8 5970's and have farted around quite a lot with different pads, paste and coolers and have finally...FINALLY found results that I'm happy with.  .5 mm pads on everything but the chip between the gpu's and the two recessed areas where I used 1mm pad.  I was really amazed how much difference a quality pad makes!

I used this pad first with mediocre results:

http://www.amazon.com/Gino-400mm-Silicone-Thermal-Heatsink/dp/B007PPEW52/ref=sr_1_1?ie=UTF8&qid=1345661952&sr=8-1&keywords=.5+mm+thermal+pad

Very rubbery, and while it was easy to handle, it just doesn't do a good job at all.  Worse then OEM on the reference cooler.

Now I've switched to these from frozencpu.com:

http://www.frozencpu.com/products/16878/thr-164/Fujipoly_Extreme_System_Builder_Thermal_Pad_-_14_Sheet_-_150_x_100_x_05_-_Thermal_Conductivity_110_WmK.html

and

http://www.frozencpu.com/products/16880/thr-165/Fujipoly_Extreme_System_Builder_Thermal_Pad_-_14_Sheet_-_150_x_100_x_10_-_Thermal_Conductivity_110_WmK.html

These things are a pain to work with comparatively speaking, but wow are they worth it!

Temps dropped by 10-15c on the VRMS! Regarding paste, the best I've found that is available locally is the Antec 7 paste.  a 5gram tube from Best Buy costs like 13$ iirc.  Temps are now great.  At 73f ambient one core is at 960/175/1.15v and the other is at 800/175/1.024.  Temps in gpuz are listed as follows:

Core 1 (960)

59c
64.5c
63c

vddc's

71c
73c
71c

Core 2 - the hotter core (800mhz)

60c
64c
62c

vddc

76c
77c
76c
vddci1 48c
vddci2 51c
 

Anyhow, I'm posting here because I finally feel like 'i figured it out' and hope it saves you all a few bucks on poor quality pads.

One other thing, use thick paste like the antec stuff...Arctic silver is too thin - I think and the pressure on the gpu is too high with the x bracket in place for that product to work properly..It seems to all get pushed out the sides once its tightened down.

Cheers!

By the way, for those white pads I used on RAM, I have to remove the non-sticky layer use a very sharp and thin knife, otherwise it is not enough thin and will make the GPU contact less reliable, I think the distance between RAM and sink is 0.6mm and distance between VRM and heat sink is 0.4mm, so those 0.5mm pads might not provide enough tight contact when used on RAM

Ok, I will try that tonight.

I also have coolant thermal pads, those 0.5mm pads should be used, white pads do not provide enough good performance.

elmers glue? you serious?

As far as VRM and thermal pads goes, I redid the whole kit n kaboodle for one of my 5870's, GPU die, VRAM, and VRM's. Used 1mm thermal pads from http://www.frozencpu.com/products/9435/thr-66/EK_Thermal_Pad_Sheet_-_160mm_x_155mm_x_1mm.html for the VRAM and VRM's and Shin-Etsu x23-7783d grease for the GPU core. The thermal pads themselves arent really that sticky I think; just really soft. 1025MHz core @ 1.125v, 205MHz RAM, stock heatsink with a blower-style fan I bought to replace the original stock one; operates near identically (4100 RPM @ 100% without any air restriction above the card).

Ambient temperature right now is 8.3C. Core is at 45C (+36.7C) and VRMs are at 52C (+43.7C) and 81.29 amps. I didn't use any thermal grease for the RAM or VRM's. I just made sure it was very clean using Goo Gone (citrus-based cleaner) and denatured alcohol to pick up the remaining goo gone. Also make sure your screws are pretty tight. They should have springs and the threading doesn't go all the way on the screw so it should be impossible to overtighten them.

If your temperatures are still wonky and you are sure you have good contact, it could be something wrong with the heatsink itself. I have 2 stock 5870 heatsinks. One of them runs about 15-20C hotter, no matter how many times I mount it. Maybe bad vapor chamber/heatpipes to heatsink contact.

Here's the contact I get with my thermal pads. This is from the 15-20C higher heatsink.

Well, because my mining farm is down for the summer, I figured it would be a good time to replace thermal pads and slap a new layer of Elmers glue on the GPU's

I tested the card with guiminer and my VRM temp skyrocketed.  They used to settle at 95C, but I turned the test off after 105C. (too risky)

I used .5mm pads for the ram and cfx bridge.

I used 1mm pads for the vrms.  This is with the stock cooler going back on.  (the pads were in terrible condition anyway and the paste was dried)


So the only thing striking my mind is the pads I used.  I researched around here and saw the .5mm and 1mm for those respective parts, so I went through with it.

I used the two pads koolance sent to me for my 7970 waterblock.  the .5mm is grey and sticky on both sides.  The 1mm (on the vrams) is sticky on one side.

any thoughts on this?