Trial & error with different pad sizes.

The most important thing I noticed is the memory & VRM pad install instructions in the EK manual are outdated for installing this block onto a 1080 Classy:
-Heights of components have changed; this reflects in temperatures on everything except the core.

-EK are shipping this block with old manual and old instructions and listing the block as compatible with 1080 Classy (this is still GOOD because):

A) They were not supporting it *officially* before I forwarded them my initial research last month.

B) it is indeed compatible and even WITHOUT doing the modifications to the instructions below you WILL INDEED still be deep within safe limits;

...however if you want the best temps; then accept that component heights have changed.
If you want the three GDDR5X memory chips closest to the VRM to run 20c cooler then you must at least change the sizes of the pads for memory & VRM to 1.0mm and 1.5mm. (These areas are marked blue in the picture)

Note: The EK manual lists these pads as 0.5mm memory and 1.0mm VRM.

-The areas marked red are for extra pads only (definitely not essential but if you want to scrape every last degree C you can add these extra pads). I've tested with trial and error to work out the best heights for these extra pads.

-Testing method for checking contact was 2 tier:
(1) brushing top of all pads with a little thermal grease; attaching then removing block, then looking at block to see if there was residue (if there was then contact was fine).

(2) to test just how good this contact is I installed temperature probes on memory and VRM areas (on back of PCB) then set my water chiller to below ambient. If a testing area dropped a good level below ambient (maybe 14c for memory) then I know contact on that area is good. (obviously the more you're pad is compressed between component and block the better; but you don't want it to be too high as this could affect the contact on components around it)

(3) Finally 2 Furmark Stress Tests; (a) GPU Core Burner then (b) GPU memory burner (temps were monitored across core, VRM & memory).
 
Image URL: http://cdn.overclock.net/4/4f/4fc7c37c_780ticlassyblockonto1080classy.jpeg (for full-size)
Or go here to read my article on this at overclock.net: http://www.overclock.net/t/1601288/official-nvidia-gtx-1080-owners-club/8740#post_25737043 

Also nearly forgot.
 
Here's link to my original post when I first worked with EK to get us official support:
 
EK_Grega was fantastic throughout.
 
http://forums.evga.com/Ne...-m2590636.aspx#2590636

AHowes
Biggest problem is finding the correct pads.. do you have a link?

Don't think I wana tear my blocks apart atm but when it's time for a coolant flush I may.

I use ebay for pads (some great deals on there).
 
Here's a link where I got mine very cheap and free delivery (or 0.70) for 1st Class (24hrs) in the U.K (international might be a few pounds more). £1 is about 1.10 in dollars. (don't know what country you're from)
 
But here's link:
http://www.ebay.co.uk/itm/262746215254?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT (10cm x 10cm 1mm 3.2 W/mk) for £2.09  (2.56 US Dollar)
http://www.ebay.co.uk/itm/200785561495?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT (10cm x 10cm 1.5mm 2.8 W/mk) for £3.95 (4.83 US Dollar)
 
10cm x 10cm will last you ages and you'll have plenty left over too.
 
If I can get them as cheap as that in the U.K I'm sure you could probably get them cheaper and better quality in the U.S if that's where you're from.
 
Or if delivering to Europe I'm sure its still only a few pounds (or Euros) more from those links.
 
Mind you even the rest of Europe seems to have more enthusiast PC stuff available than the U.K so really you should be able to find good pads.  Just stay away from anything not at least 3 w/MK (approx.) if buying on Ebay. 
 
If you're buying from a reputable (known) supplier 1 w/MK is fine (you won't notice the difference). Just make sure they are quoted as 'soft' or 'easily compressed'.  Most decent pads will compress to 50% their original height with only certain pressure.
 
I bought the ones in the links I gave you and my memory is overclocked at +925with no errors.
 
Hope it goes well for you,
 
Nick

AHowes
Ok thanks.. and it's hard to read the numbers in your pic for the pads.. for the red pads "VRM area" from left to right the numbers are?

If you go to this link you can see the image in its full size which makes it much easier to see the numbers:
http://cdn.overclock.net/4/4f/4fc7c37c_780ticlassyblockonto1080classy.jpeg (once you get to the link if you move your cursor over the picture it should also turn to a magnifying glass) so you can zoom in, even further :-)

Hey! 
I'm wondering if there is any backplate that will fit my GTX1080 Classified after installing EK780 Classy waterblock. Will the 780 Classy backplates fit aswell or do I have to use the original 1080 Classified backplate if I want one?
 
Best regards,
Linus