I only changed the rear pads, and for those I used 1.5mm. I wouldn't have thought that would improve contact on the front of the card though. And I can only think that adding a support improves contact for the front pads.
There is a lot of hersay about warranty and changing pads. The offical line from nVidia of course is that if you open or modify the card in anyway, your warranty is void.
However, I have not personally seen a single instance of nVidia refusing an RMA for any reason.
In one case on this board a user even admitted to them he had opened the card. In another reddit case, the user simply didnt mention the changed pads.
Personally, I tend to believe that nVidia operates by simply not checking.
If a card comes to them that appears physically perfect, and fails its bench testing I imagine they just move on and approve the RMA, send a replacement.
I could only see them rejecting a claim if either the user admits they modified the card to them when opening the claim, or the card arrives at nVidia obviously damaged or modified.
If I ever need to RMA my card, I certainly wont mention the changed pads. IF nVidia then tried to reject my claim based on changed pads, Id put up a fight. Hoping they back down. But yes, I would say the risk exists they dont and I am out of pocket. Still, I consider that risk to be miniscule.
Thats just my $0.02 on it.
The stock REAR pads are 1.0mm and the stock FRONT pads (VRAM) are 1.5mm.
The stock front VRM pads are 1.8mm-2.0mm (apparently left is 1.8mm and right is 2.0mm. Not sure about the 'solo' isolated VRM pad, probably the same as the right one).
The heatsink is obviously one piece (it can move freely like a couple of mm or so within the shroud when you have the PCB removed) and the PCB obviously attaches directly to the heatsink via the X bracket "Leaf spring".
HOWEVER
it appears that *ONLY* the leaf spring X bracket is what attaches the PCB to the heatsink!
Look carefully.
You can see that the I/O (Torx T8) screw on the bottom left, and the four Torx T5 screws (around the edges of the heatsink on the left) ONLY attach to the OUTER SHROUD and NOT to the heatsink!!!!!!
The same goes for the four phillips screws on the V section.
And what does the backplate screw into?
The OUTER SHROUD. NOT to the heatsink! So those "backplate screws" that you screw in, while there IS a connection for the screws on the edges of the PCB, those screws have no connection to the heatsink itself. So the backplate doesn't have any real "secure" mount to the PCB and none to the heatsink. Yes it goes on but...
So the heatsink has some play (X/Y axis) with the PCB removed, but also some Z axis play too. (what's keeping it in place from falling out completely seem to be two hidden latches, shown in GamersNexus' teardown video, which are extremely difficult to reach, which are also required to unlatch if you ever need to remove the fan cable that is taped to the shroud (one of them is not taped and comes out just by unscrewing the fan).
Now, it's obvious that the heatsink attaches to the PCB and there's not going to be any play on the PCB to heatsink itself.
But the backplate has no direct connection to the heatsink. Only to the shroud. So if the backplate thermal pads are too thin, the heatsink is still going to have some play.
When you guys are pushing the 'front' area in (from the bottom), you're pushing the heatsink up towards the backplate. Which would then improve the connection of the *PCB* to the backplate.
Whoever swapped the 1.0mm backplate VRAM pads for 1.5mm or 2.0mm is automatically reducing or removing the amount of Z axis play as the thicker thermal pads will compensate for any sort of give.
So this stands to mean that 2.0mm VRAM backplate thermal pads (Gelid Ultimate or Gelid Extreme) would entirely solve this problem here. While even 1.5mm pads would still be better than the stock 1.0mm original Nvidia pads.
Looks like the left and righit "hotspot" strips have a larger impression than the VRAM pads in the middle, implying firmer contact. Once those sections are compressed, they won't decompress. Oh whatever.