How much should thermal pads be compressed?

[pqwoerituytruei]

I have a backplate on a GPU that i want to add pads to. I have a 2.5mm gap to fill should i use a 2.5mm pad or should i use 3mm?
perhaps i should add a thin piece of aluminum so i can use a thinner pad

 

[trents]

I'm not sure that compressing the thermal pad would have any negative impact. If anything, I think it would be a positive impact as long as the contact surface of the heat sink isn't distorted by the pressure. Now, I'm assuming this back plate is serving as a sink.

 

[pqwoerituytruei]

i do not want to flex the pcb too much is why i am asking

back plates are only good for 2 things, adding structural integrity and sinking heat

 

[EarthDog]

0.5mm of a thermal pad will not flex the PCB or heatsink. They are very soft and will compress easily. You see this on factory installations as well. Get 3.0mm for a 2.5mm gap.

 

[pqwoerituytruei]

thanks, there is a stock pad near my vrm, it is 1.5mm <.< for a 2.5mm gap so it dose nothing...
is staking pads bad?

 

[Mr.Scott]

thanks, there is a stock pad near my vrm, it is 1.5mm <.< for a 2.5mm gap so it dose nothing...
is staking pads bad?

Not preferred, but not as bad as no contact.

 

[pqwoerituytruei]

I think i will take some thermal adhesive and attach some aluminum bars to the plate and put thermal pads on that, thermal adhesive, aluminum, and a thin pad has to be better than a thick pad