I recently took my GTX 680 apart, removed the stock TIM, lapped the GPU heatsink, added Arctic Silver 5, added the EVGA back-plate, replaced the stock bracket with an EVGA high-flow bracket, put it all back together, and benchmarked the temps. At the very bottom of this post are step-by-step directions for the whole process.
The results are more impressive than I expected!

And the curing time for Arctic Silver 5 is 50 to 200 hours, so the temps may drop another 1C, if at all.
(click on image thumbs for full size) Photos of the Process I upgraded from an EVGA GTX 295 Co-Op card. The 680 is quite a bit shorter. On that note, I had a piece of metal on the back of the 295 to direct exhaust away from the card's intake fan. The cooling design on the dual-GPU cards always irritated me a bit since half of the heat was dumped inside the case. It's sad to see the 690 does that same darn thing.
GTX 680 installed in my PC, before the mod.
GTX 680.
The plastic housing is very easy to remove, more so than some past gen models.
EVGA Back-plate and High-Flow Bracket.
GPU Heatsink removed.
TIM on GPU heatsink is thick. Not horrible, but not great. But worse were these odd fibers on one side. You'll need to look at the image full-size to see those fibers.
TIm removed and surfaces prepped.
GPU heatsink doesn't have a smooth finish; it's just roughly machined.
Close-up of the stock surface for the GPU heatsink.
600 and 1500 grit sandpaper will be used. I could go as far as 2000 grit, but to be honest, there's not a huge difference, especially when you end up wearing down most of the sandpaper's grit with consecutive polishes.
Always lap heatsinks on a super-flat glass surface. Any other "flat" surface" might have imperfections. And I always spray water before each polish, even with the 600 grit. The 600 grit is used to remove surface down to the grooves/scratches that the manufacturing process creates in the copper. Then the 1500 is used to remove the 600 grit scratches.
And finally rubbing compound, polishing compound, and swirl remover help remove the 1500 grit scratches and polish it to a near-mirror like finish.
View of High-Flow Bracket.
View of EVGA Back-plate.
Temperature Benchmarking Note: If I set the card to 100% fan, it always shows as 85%. I'm not sure why. Is this a preset limit? The fan *sounds* like it's at 100% since it's pretty loud at this level. Either way, when I mention the fan being "at full", I'm referring to this value.
Ambient temps in testing area: 68F (20C)
Before (stock, fan at full)
Idle:
29C Load:
74C After (lap, high-flow, fan at full)
Idle:
25C Load:
58C - 59C Idle Stock card, idle temps with fan on auto...
After mods, idle temps with fan on auto...
Stock card, idle temps with fan at full...
After mods, idle temps with fan at full...
Furmark burn-in test, window-mode @ 2560x1600 max settings Tests ran for 5 minutes and 20 seconds.
Stock card, load temps with fan on auto...
After mods, load temps with fan on auto...
Stock card, load temps with fan at full
After mods, load temps with fan at full
Furmark 1.9.1 Burn-in test, full-screen @ 2560x1600, max settings Tests ran for exactly 5 minutes.
Stock card, load temps with fan on auto...
After mods, load temps with fan on auto...
Stock card, load temps with fan at full...
After mods, load temps with fan at full...
Step-by-Step Directions and Tips Note: this does
not void your warranty
unless you try to return a card with a lapped heatsink. There is a work-around though: just swap the lapped cooler of your defective card with the stock cooler of your replacement card for a cross-ship RMA. After all, you don't want to have to go through the whole process of lapping another heatsink for your replacement. According to Jacob:
EVGA_JacobF
Unfortunately yes, but the possible way around is to do a crosshipment, then when you get the new board in swap the heatsink.
Of course if you do this, you take full responsibility for your actions. I don't encourage anyone doing this unless they've lapped heatsinks before (it's best to practice on a spare heatsink in case you take off too much of the contact area).
- Start with a clean work area that won't be damaged by moisture or metal dust, and where you can occasionally ground yourself. You'll need:
- A #0 Philips. Optional: T6 Torx driver if you're installing an EVGA Back-plate.
- Your own thermal paste.
- Thermal paste remover & surface prep solutions.
- Paper towels or napkins, and Q-tips. Both for cleaning up in-between polishes and for removing thermal paste.
- A clean micro-fiber cloth to surface-prep the heatsink and GPU surfaces, which should completely remove dust immediately before applying thermal compound and setting the cooler on top of the GPU.
- Decent size piece of flat glass, or a glass table.
- Hairdryer or heat gun.
- Fine sandpaper (400-600 grit) and Clearcoat sandpaper (1500-2000 grit). Make sure they're functional for both dry and wet sanding. You can use almost any grit you like for taking down the copper to the bottom of the scratches/grooves made during the manufacturing process. The higher the grit, the more work you'll have to do, and the lower the grit, the bigger scratches/swirl marks you'll make on the bottom of the cooler.
- Some duct tape or a way to hold the edges of the sandpaper to the glass.
- Spray bottle filled with distilled water. You can use tap water, but hard water (water with minerals/chemicals in it) will make the process take a little longer and force you to clean-up more frequently in-between polishing.
- Polishing compound. Optional: rubbing compound and/or liquid polish/swirl remover. Whatever you choose, it should be something that can go beyond the 1500-grit wet sanding for a finer polish. Avoid polishes that include wax. You do not want to condition or add anything to the heatsink's surface. You only want to polish it to a shine to remove near-microscopic scratches.
- Remove the 680's plastic housing (cover). This is removed with six small Phillips screws, three on both the top and bottom of the card, along the edges. One of the screws at the top is on a corner, at an angle. Once these screws are removed, the cover will easily separate. Set it aside.
- Flip the card over and located the four larger Phillips screws on the back, the ones with small springs under them (the other screws should be Torx). Unscrew these larger screws while supporting the GPU heatsink (the one with fins) on the other side. Gravity should be enough to let the heatsink drop off when the screws are removed. If not, gently pull the heatsink away.
- Remove the thermal paste from both the heatsink and the GPU surfaces. Be careful not to apply too much force to the exposed resistors around the edge of the GPU. These resistors are coated to protect them from thermal paste overflow, so you'll most likely have some overflow on them. When in doubt, blot, do not wipe. Once you know where they are, you can gently wipe them clean using thermal paste remover solution that's applied to Q-tips. Just about anything can create a static charge, so be careful. Two-step removers help as the second-step (surface prep) will neutralize and clean up the residue left by the first-step remover.
- Set the card aside and prepare your lapping area. Using a flat piece of glass or glass table.
- Attach a good sized sheet of your lowest-grit sandpaper with duct tape. Make sure the paper is tight. To do this, attach one corner, then pull on the paper a bit and attach the opposite corner. If done correctly, the sandpaper will curl up a bit on the other two corners. Repeat for these corners. As the sandpaper gets saturated with water, it will relax and stretch just a little. That's why you want the sandpaper taped tightly to the glass. All of this will help you polish smoothly without stutters.
- Spray a decent amount of water on one area of the sandpaper, then a little on the bottom of the heatsink. You will always be wet sanding to reduce excessive scratching. While holding the heatsink, contact-side down on the sandpaper, polish in even, circular movements. Keep polishing until the water around the cooler turns almost completely copper-colored. When that happens, use paper towels to blot the sandpaper and wipe off the heatsink's contact surface. Repeat until the scratches/grooves made by the manufacturing process are completely gone. It's ok to stop when the area that touches the GPU's surface is done. Since the heatsink won't be 100% completely flat, those existing scratches/grooves might still show at the edges.
- Repeat steps 6 and 7 with your finer grit sandpaper. Repeat for as many stages of different sandpaper you plan to use. The fewer grades you use, the more polishing effort required.
- Thoroughly clean the heatsink's contact surface.
- Use polishing compound to polish the heatsink's contact surface to a mirror-like shine. It doesn't have to be absolutely perfect. Not only will this make it look amazing, but this helps to smooth out any near-microscopic scratches left by the wet sanding process.
- Clean the heatink's contact surface with your thermal paste remover and surface prep solution.
- Dry the entire heatsink with a hairdryer or heat gun on lowest settings. Make sure it gets pretty hot to force any residual moisture to evaporate. Then set the heat sink aside for a couple of minutes.
- If you're installing an EVGA Back-plate at the same time, as I did, now's the time to mount it. Note: do not remove your sticker with the EVGA serial number as this will void your warranty. You can place the back-plate right over top of it. The foam on the back-plate is not thermal foam, as it is just there to protect the area around the GPU. Use a T6 Torx driver to remove the Torx screws from the back of the card that line up with the back-plate. Do this while supporting the fan and black heat spreader. If done correctly, you'll only have two Torx screws left, both near the top edge of the card. Place the plate on top of the PCB and line up the holes. Attach it to the card with the provided screws (not the existing stock screws). These screws are #0 Phillips instead of the default Torx.
- Get ready your four Phillips screws with attached springs that were included with the back-plate.
- Flip the card over and get your heatsink ready.
- Use a micro-fiber cloth to remove any last-minute dust that might have collected on the GPU's and heatsink's contact surface.
- Apply a little less than a pea-sized drop of thermal paste directly in the middle of the GPU. The general rule of thumb is a pea-sized drop, but even that is too much for this small nm scale GPU. If you use too much paste your temps will suffer a bit, but you're still protected. If you use too little paste, it won't completely cover the GPU and your temps will suffer by having gaps on the edges. It's certainly a balancing act.
- While holding the heatsink in place, flip the card over and mount the heatsink with the four spring-attached screws. Don't tighten them all the way. Screw them in gently until they make contact. Then tighten them down in a crisscross pattern: start with one, tighten a bit, then tighten the screw across from it, and repeat. This ensures that the heatsink cooler is tightened as evenly as reasonably possible. Doing so will spread the paste out evenly from the middle.
- Flip the card over and reattach the cover with its six screws.
- If you're adding the high-flow bracket, remove all connector covers (the soft plastic protectors) first. Then use either a small socket driver or needle-nose pliers to remove the hex standoffs around the DVI connectors. Use a #1 or #0 Phillips driver to remove the two screws on the back of the bracket. Then use a #0 Phillips to remove the screw at the top edge, where the bracket has a tab that connects to the back of the card. Install your high-flow bracket and reattach with the standoffs and screws. Don't replace the connector covers until after you've install the card in your PC. I've noticed that the high-flow bracket is just a little off from the stock bracket, so this difference makes some of the DVI connector covers get in the way.
- Install your card and test. Enjoy!
<message edited by cipher_nemo on Monday, April 30, 2012 10:24 AM>