So I couldn't get a definitive answer on thermal pads for the FTW3 so I took a punt and bought an assortment of Primochill stuff to replace the memory and VRM pads on my FTW3 ultra and thought i'd share what I learned.
 
Firstly, the memory needs 2mm thermal pads. The best info I could find suggested 1mm pads and I ended up needing to double them up on the memory. I actually ended up running out of pads because of this which led to me not quite getting full coverage on my VRM's
 
VRM's need 1mm thermal pads. I can see why they used thermal putty after pulling it apart because they are not uniform height, their height varies quite a bit which is what the thermal putty works well with.
 
The backplate needs 3mm pads if you want to get some contact on the back of the memory, that gap is quite large.
 
Now before everyone flips out at the amount of thermal paste in my photo, I took it before I had scraped it off to a thinner layer. Thermal performance after re-fitting the cooler with the thermal pads and fresh paste is basically the same, GPU2 temperature is slightly improved and I have managed to squeeze an extra 25MHz core out of Timespy on ambient air cooling, so it looks like I have managed to derive some slight benefit from it.
 
The OEM thermal paste was nowhere near as dry and crusty as the Gamers Nexus one was in their teardown. The thermal paste on my card was evenly applied, not too dry and cleaned off very easily.

sparetimepc

Reedey
So I couldn't get a definitive answer on thermal pads for the FTW3 so I took a punt and bought an assortment of Primochill stuff to replace the memory and VRM pads on my FTW3 ultra and thought i'd share what I learned.
 
Firstly, the memory needs 2mm thermal pads. The best info I could find suggested 1mm pads and I ended up needing to double them up on the memory. I actually ended up running out of pads because of this which led to me not quite getting full coverage on my VRM's
 
VRM's need 1mm thermal pads. I can see why they used thermal putty after pulling it apart because they are not uniform height, their height varies quite a bit which is what the thermal putty works well with.
 
The backplate needs 3mm pads if you want to get some contact on the back of the memory, that gap is quite large.
 
Now before everyone flips out at the amount of thermal paste in my photo, I took it before I had scraped it off to a thinner layer. Thermal performance after re-fitting the cooler with the thermal pads and fresh paste is basically the same, GPU2 temperature is slightly improved and I have managed to squeeze an extra 25MHz core out of Timespy on ambient air cooling, so it looks like I have managed to derive some slight benefit from it.
 
The OEM thermal paste was nowhere near as dry and crusty as the Gamers Nexus one was in their teardown. The thermal paste on my card was evenly applied, not too dry and cleaned off very easily.

Look at the last entry here in this post from evga direct.

https://forums.evga.com/m..aspx?m=3122199&fp=8

Would the 3080 be the same thicknesses? 

disregard I had wrong card

Reedey
So I couldn't get a definitive answer on thermal pads for the FTW3 so I took a punt and bought an assortment of Primochill stuff to replace the memory and VRM pads on my FTW3 ultra and thought i'd share what I learned.
 
Firstly, the memory needs 2mm thermal pads. The best info I could find suggested 1mm pads and I ended up needing to double them up on the memory. I actually ended up running out of pads because of this which led to me not quite getting full coverage on my VRM's
 
VRM's need 1mm thermal pads. I can see why they used thermal putty after pulling it apart because they are not uniform height, their height varies quite a bit which is what the thermal putty works well with.
 
The backplate needs 3mm pads if you want to get some contact on the back of the memory, that gap is quite large.
 
Now before everyone flips out at the amount of thermal paste in my photo, I took it before I had scraped it off to a thinner layer. Thermal performance after re-fitting the cooler with the thermal pads and fresh paste is basically the same, GPU2 temperature is slightly improved and I have managed to squeeze an extra 25MHz core out of Timespy on ambient air cooling, so it looks like I have managed to derive some slight benefit from it.
 
The OEM thermal paste was nowhere near as dry and crusty as the Gamers Nexus one was in their teardown. The thermal paste on my card was evenly applied, not too dry and cleaned off very easily.

where did you source your 3mm pads for the backplate? did you have a shot of where you applied them?

streamroller
How come you missed the most important comparison here
 
Stock Thermal pads vs Aftermarket Temps
 
You mentioned gpu2 ( backside) now cools better but how much ?
 
Also how about gpu core and mems ? I guess EVGA already used quality materials on pads.

Thermals are essentially the same across the board. No real measurable difference in temperatures, however I have gained the extra 25MHz so it has maybe done something. If I didn't have to double up on some of the pads then my result would probably have been better.

Does anyone know what the thermal conductivity specs are for the pads and putty used by EVGA on the 3090 FTW3 Ultras? I wanted to replace mine but I wanted to make sure i meet or exceed the technical specs for the material I select. So far I am considering Fujipoly Premium with a thermal Conductivity 6.0 W/mK. I was thinking the Ultra with 17.0 W/mK maybe overkill, or will the memory chips need the higher spec pads?

6 W/MK PADS good enough to use > ?? 

Most likely. Getting good contact with everything is much more important.