Reddit reviews Vktech Heatsink Copper Shim Thermal Pads for Laptop GPU CPU VGA 30Pcs 15mmx15mm

Would you be able to post some pictures? Particularly of this square cut out you're referencing. That'll help us give some advice.

It's possible you'll need to use a shim to be able to get proper contact. It'll be something like these that will go between the H55 and the GPU die (with thermal paste used on both sides of the shim). Just make sure you get a size that will fit over the entire GPU die for the best contact possible.

Use 10x10mm heat sinks for the rear two voltage regulator transistors. I used 15x15mm copper heatsink shims to create the custom heat sinks for the 4 small transistors around each single opamp. These were the shims I used, 1mm seems a good thickness, but slightly less like a 0.8mm would be fine as well:

https://www.amazon.com/gp/product/B00E5SMY0W/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1

They were bonded to the transistors using this thermal epoxy (which also was added to the cut and bent corner intersections for better conductivity/efficiency of heat away from the transistors):

https://www.amazon.com/gp/product/B0087X7262/ref=ppx_yo_dt_b_asin_title_o09_s01?ie=UTF8&psc=1

Picture of the adhered custom heatsinks before I added the epoxy to the gap intersection:

https://photos.smugmug.com/photos/i-6NjDqDM/1/94baa3bf/O/i-6NjDqDM.jpg

Have Classic duals and Vivid singles, which is what I settled on after having full set of both. Difference is not night and day, but is noticeable side by side over stock. Some headphones are slightly preferred on stock (mainly the planarss) while others are more preferred with the Bursons (modded HD58X and TH-X00s). The Porta Pro's can swing either way.

Stock opamps are not as clean or resolving sounding, little less separation and not as tight sound as the Bursons. There are other opamps besides Burson which are much cheaper. Head-fi Gustard H10 thread has some impressions of different opamps in it. The Bursons are an improvement in fidelity, but basically almost double the price of the H10...

Also don't be weirded out by the slightly bipolar nature of the H10's sound until it seemingly settles down (if it is apparent). It seems H10 will initially sound good, then get worse, then come back and sound better, maybe fluctuate a bit after that, and finally just keep getting better. Very much seems to be everyones experience with it within the frst few hundred hours of use.

I believe you need to add a copper shim if you decide to go with G12 route because of EVGA's baseplate design Either remove the baseplate entirely or also add in a copper shim in order for the aio to make proper contact.

Another air cooler I recommend and currently using is the Rajintek Morpheus II It doesn't come with any fans, but you can attach with your favorite 2 120mm case fans which will be far more superior than regular vga fans. Downside is that it will take roughly 3.5 slots when you add the fans. I'm only averaging 60C max under load with my OC gtx 980 ti while maintaining high clocks with it with 2 Noctua nf-f12 ippc fans attached.

If you look up "thermal pad" on Amazon, buy one that is thick enough to fill the gap. I would imagine the thicker ones would fill the gap. You can also ship that gap with a copper shim https://www.amazon.com/Vktech-Heatsink-Copper-Thermal-15mmx15mm/dp/B00E5SMY0W/ref=sr_1_15?ie=UTF8&qid=1500310505&sr=8-15&keywords=thermal+pad

Or sand down a (copper!) penny and call it a day. Make sure to use thermal paste if you do so.

You can try to use thermal paste if you want, but the air gaps on these not-very-precise heatsinks aren't designed to be filled with traditional thermal paste. The thermal paste will likely act as a thermal insulator at that thickness.

Hope this helps...

Ninja edit: By the way, in the future, you can fix the noise just by blowing out your heatsinks. Make sure to stick something in the fans to prevent them from spinning, because canned air will cause the blades/motor to spin much faster than the bearings (if applicable) are designed to spin, and it can burn them out, actually making the problem worse. Many times on these older machines you don't even need to disassemble at all (sometimes just removing one plate) to make sure the blades don't spin.