Pro tip: thermal pads are not always the answer

I used to think slapping thermal pads on every hot component was a safe bet... until last month when I worked on a gaming laptop from 2019. The VRMs were hitting 110C under load and I figured pads would fix it. Turns out the heatsink had warped just a tiny bit and the pads were too thick, making things worse. I ended up using a thin layer of decent thermal paste on the VRMs instead and the temps dropped 15 degrees. Sometimes the cheaper, simpler fix is actually better than the fancy stuff. Anyone else run into a situation where the obvious fix backfired like that?

3 comments

3 Comments

knight.uma2d ago

Wait, hold up. A warped heatsink on a 2019 laptop? That's bananas. I've seen some janky manufacturing defects but a heatsink bending just enough to mess with pad thickness is next level. How does that even happen unless someone dropped it or it got cooked in a hot car? Did you check if the laptop was dropped before you cracked it open? That's wild. I usually just assume pads are a safe bet too but now you got me paranoid about checking for warpage. Never would have thought to use paste on VRMs either, that's actually genius for a tight clearance situation.

alex8201d ago

Whoa, hold on @knight.uma, I gotta push back on something there. That paste on VRMs trick is actually pretty risky if you're not careful. See, thermal paste isn't meant to conduct electricity at all, but some pastes are actually capacitive and can cause shorts if you use too much. For tight clearances, a better move is to use a thermal pad that's just a hair thicker than you think you need, then squish it down with the heatsink. That way you get full coverage without the risk of paste seeping out. But yeah, the warped heatsink thing is a real head-scratcher. My guess is it's from uneven pressure during assembly or maybe a bad batch of aluminum. Never assume the heatsink is flat, always check with a straight edge or a good ruler.

milalewis1d ago

Has anyone else noticed that some thermal pads out there are just junk from the start? I read a teardown once where a guy tested a bunch of cheap pads and half of them were way off in thickness, plus they crumbled after a few months. So even if your heatsink is flat, a bad pad can cause the same issue. On the VRM paste thing, I've seen people use that trick with non-conductive paste like MX-4 or something similar, and it works fine as long as you don't glob it on. But yeah, always check your parts first, don't just trust they're good.