Better Cooling for the 7800GTX - Page 11

Benchmark on high performance settings, everyone else does , and that's worth ~200pts.

Wow, beautiful place you have there Doc . RTHDRIBL is a great program, but it's too old to bring these cards up to max temperature. FEAR, ATiTool, Far Cry w/ HDR, and Splinter Cell: Chaos Theory are the most taxing I've found.

I re-applied my AS5 to a VERY thin layer and it dropped temps 5-6C or so. So now I'm loading at 98-100C in I9KFanGUI. Still too hot in my opinion, but the card doesn't seem to have any problems. I think I will add the copper shim tomorrow. I think the problem with the heatsink is that it doesn't put enough pressure on the core to insure proper contact. I still think there is too much of a gap. Anyway, I'll see tomorrow .

LOL! Oh man, looks great, just dont take that last step off the back porch .

And yes! You answered the question before I could. That "grain of rice in the center" method is ONLY for CPUs WITH an IHS (heatspreader). All other, uncovered CPUs, GPUs and chips MUST have the entire surface of the chip (the glass, silicon part, not the green cermanic, that'd fry it ) be covered with AS5 to ensure complete contact with the heatsink. Otherwise you can heat stress fracture the silicon in the chip (over a period of time). The way I'm doing it now, without a shim, I apply a small dab in the middle of the core. Then I take a plastic microscope slide (+ point of being a biochem and molecular bio major ) and spread the AS5 over the entire core. I then scrape off any excess so that there is a relatively thin layer on the core. NEVER USE A RAZOR OR ANY METAL OBJECT. Depending on the metal used, it can scratch your core! Then, with the heatsink off the back side of the card, I put the front part on and press it against the core and rotate it slowly back and forth to ensure connection and that the AS5 is spread out, air bubbles are released, and that it is pushed into microscopic gaps. Then I put the back plate on and screw it all together. I'm still loading at 100C in FEAR (was 104C+ before) and 92C in Serious Sam 2 (HDR lighting). I dunno, I would like it to be lower, but the card is 100% stable. I'm going to try putting on the copper shim tomorrow for the heck of it. I'll see how much it lowers temps.

Yah, I have one of those wands too, but I like the bigger surface of the microshope slide. Still, it is great and can't be beat for applying their adhesives . Btw, welcome to the "I have killed a vid card club"

I wish that arctic silver would do a better job of separating its directions for different applications. The razor can be used on the large IHS (heatspreaders) of desktop CPUs, as those are metal and will not be harmed by the razor. It CANNOT be used on an open CPU core, nor can you use it on a heatsink as it can scratch the copper/aluminum. It's always best to stick to plastic or some softer material, refer to Moh's hardness scale in case you're wondering what else to use .

Yup, they're spring loaded. That's why they have lock washers on the bottom of the screws so that they meet the PCB and cannot screw in any further, so that the rest of the compression is due to the springs. What's the problem with this? The springs don't apply enough pressure. For example, desktop CPU's have a compression weight of I think 60-70lbs (I'll have to look it up exactly), and that's one reason why they run so cool: the mating of the surfaces is basically flawless. Do you think those dinky springs on the CPU heatsink or the GPU heatsink provide that kind of pressure? That's why you add the copper shim, so that it adds more pressure on the core

ALL HAIL THE SHIM .

I just installed it after filing it down a tiny bit (it's probably 0.020" now or so), and although I managed to file off a finger nail or two in the process, it worked . Load temps in FEAR are now 90-91C and it idles at 46-47C instead of 49-50C. Installing the shim is a pain in the ass though. First, I put a thin layer on the core (VERY thin, almost transparent) and pushed the shim on the core with a bag over my finger, and then rotated the shim while applying pressure to it. I then rubbed AS5 into the heatsink using my plastic bag covered finger, and wiped away any excess with that bag covered finger. Finally, I smoothed out a thicker layer of AS5 on top of the shim. I then took the back plate off and pushed the heatsink on to the shim. I then rotated the heatsink EVER so slightly in both clockwise and counter clockwise circles in order to make good contact but not move the position of the shim. Finally, I tightened the screws until they locked, and then loosened them about 1/2 to 3/4 of a turn so that the springs had ever so slight give (barely detectable). Anyway, it works like a million bucks .

To review the temp changes:
Stock - God knows what, probably would have melted the plastic
Thick layer of AS5 - 104-105C in FEAR
Thin layer of AS5 - 100C, but note that the first attempt left a part of the core with no contact to the heatsink, although it was covered with a layer of AS5.
Thin layers of AS5 + shim - 90-91C load, gold

Master Axe - believe it or not, cards, mobos, chips, and what have you can take a beating as long as it isn't jarring or sudden. Compression doesn't really hurt the chip until you tighten a screw over it and crack it (which is very difficult to do with spring loaded screws).

strat- don't worry about the thickness that much man, that's what the rotation is for. If it's too thick, it'll push excess out to the sides . Strive to put on a very thin but opaque (for the most part) layer of AS5. The rubbing action is really important because it ensures good contact and fills all the microscopic valleys. If you want to rub AS5 into the heatsink, cover your finger with a plastic bag and use that to rub it in. Using any kind of cloth will still get debris in the AS5. The core, is, essentially, the texture of glass, so there are no valleys to fill in, so dont bother rubbing AS5 into it before applying.