MOSFET cooling needed?

JamieH · 14 Oct 2009 at 14:05

So I have a DFI LANPARTY DK X48-T2RS motherboard and I have just purchased a Zalman CNPS9500A cpu cooler. The problem is it won't fit properly with MOSFET heatsinks on the board. I was going to swap out the NB heatsink for that Alpenföhn Ötzi Northbridge Cooler. Would it be okay just to leave the MOSFET's bare? Do they really need heatsinks? Thanks.

That's the board below:

gurusan · 14 Oct 2009 at 16:11

Sorry but yes they absolutely need some sort of cooling

biuro74 · 14 Oct 2009 at 18:56

gurusan said:
Sorry but yes they absolutely need some sort of cooling

It's good that's someone I can ask

I've got a mobo with Stack'N'Cool2 system - heat from SB, NB and nForce200 goes through heatpipes to mosfet's heatsinks placed around the CPU socket and by default they should be cooled with air pushed by standard CPU vertical fan.

It's what I get.

But I've done a thermal paste change - I took off the whole Stack'N'Cool2, ripped off the old conrete-like paste and applied Zalman STG1. Temps of course decreased significantly. But.. but.. I've noticed the mosfet's parts of heatsink had some kind of material underneath - it really looks like heat isolator.
Moreover, I've bought alternative, complete chipset air cooling which contains mosfet heatsink as well. That heatsink has got the same - material sticked underneath. As far as I know such materials are not thermal conductors, so is it possible that mosfet's heatsinks are used just as heat spreader for heat transported from chipsets only ?

JonJ678 · 14 Oct 2009 at 18:59

Nope. That thick, grey pad is used to transfer heat from the very uneven surface of the mosfets onto the heatsink. As evidence I offer the boards with mosfet heatsinks that are separate from the northbridge.

However, by the same token you can buy boards with no mosfet heatsinks. This suggests that they'll work bare. However they'll run hot, and I think will limit your possible overclock. It's possible that you wont be stable at stock settings and/or will damage them by attempting this.

The better idea is to send the cpu cooler back and get a different one. Sorry man.

JamieH · 14 Oct 2009 at 19:57

I sorted out the problem. It involved a hack saw and my DFI motherboard.

Helios1234 · 14 Oct 2009 at 20:10

On my biostar x58, I wanted to change the NB cooling but since all the heatsinks were attached including the Mosfets ones, I had to get those as well.

I bought the Thermalright HR-09 type 2 for the Mosfets but it didnt fit and I ended up buying some Swiftech vga mosfet heatsinks. They were designed for graphics cards but seem to work well. My only complaint is that they don't stick on very well, so I bought some Sekisui Thermal Adhesive Tape for reassurance.