Originally Posted by
controlyar
The 5970 reference design uses the *best* available components for both board and heatsink construction - I mean that quite literally.
It is critical that if the cooling solution is replaced, VRM cooling is seriously taken into consideration when selecting a replacement cooling solution. The Volterra regulator slaves (small shiny silicon components) must be kept cool for proper operation (125C rated, 150C shutdown) and to prevent the board from throttling clocks (typically at 125C).
The only recommended thermal interface materials (TIM) are:
Volterra Slaves (small shiny components) - T-Pli 225/230 - 230 is slightly thick and is easier to handle , best TIM available @ 6W/m-k
GDDR5 Memory/Inductors - black components (some marked CPL/Cooper/Pulse) - thin conformal pad, high thermal conductivity - few available
If the inductors are not thermal coupled to the waterblock, the waterblock will encase the part and allow it cook in this environment.
If you are "upgrading" to a liquid cooling block, you may want to carefully consider transferring the thermal material to the waterblock. It can be removed and kept intact with a fine blade.
To validate the VRM cooling is working , you can look at the graph/logs of GPU-Z for the VDDC Phase #1/2/3 temperatures running your favourite application - the readings are very accurate and directly reflect the regulator silicon junction temperatures.
I have seen single piece waterblocks struggle to provide adequate pressure to all components on such large dual GPU boards - there are many components to cool and it is very challenging to perform this function using a single piece of CNC'd copper. The tolerances are extremely tight, so you may have to overtighten screws to help pull the copper plate against the board - but then you risk damaging board components.
Otherwise, contact the manufacturer (DD/EK/Coolance etc.) and request that they consider using the same thermal interface materials as used on the reference design in the future.
Feel free to post this info on other forums. Much of it applies to other boards as well.
As an aside, I would not recommend running Furmark - it will only thermally stress your hardware (potentially shortening its useful life) and provide little indication on stable overclock speeds, which is the main reason users generally run it. The board may also throttle speeds, which again will not provide any insight into the maximum achievable speeds.
