X240 iGPU not touching heatsink

[thealphaoverseer]

Hi everyone,
I've run into some crashes lately and only when gaming, so I've narrowed down the problem to the iGPU. I believe there used to be a thermal pad which connected it to the heatsink, but unfortunately it's gone now. Several months ago I put a giant blob of thermal paste to do the job but now that I'm using my X240 as a daily driver I'd like to replace it with a copper plate.
How thick should it be? Do I just use trial and error?
Where can I get copper from (I'd prefer if I didn't have to order online), and how can I cut it?

Thanks!

[axur-delmeria]

The integrated graphics is part of the CPU die (the big glass-like silicon rectangle that is covered by the heatsink, as seen on the photo below.
The small silicon die beside it is the PCH (platform control hub) which handles peripherals like the USB and SATA ports. AFAIK that shouldn't make contact with the heatsink's copper plate.



You probably need to clean the fan and cooling fins on the heatsink. Putting too much paste is actually a bad idea.

[thealphaoverseer]

Thank you! I have learnt something new.

The fan appears to be clean. I feel like the silicon is showing its age. My other X240 was fine before, but is also crashing under load. Both idle around 55 and reach 75-85 when web browsing, which is quite toasty (I'm using TPFC and undervolting).

[thealphaoverseer]

Just out of interest though, how much worse is the airflow when docked?
I happen to require 4 USB ports, but can do without if it improves performance.

[RealBlackStuff]

An X240 with i5 CPU, a clean working fan and properly applied thermal paste should idle in the low 40s C.
Even when online gaming it should not go over the mid 70s C.
If it has an i7 CPU, add maybe 5 C to those temps.
And this is without fan- or throttle- or undervolt-programs.