Dell Latitude E6400 heatsink

I'm not sure if others are aware, but I have recently found out that the contact between the heatsink and the GPU and chipset are made of a metal-foam material, while the CPU's is copper with thermal paste. After doing some research, it's said that these "high-performance foam heatsink" provide "high thermal conductivity, high internal surface area, and the connectivity of the voids". I'm not sure I'm buying into this since my idling temps are about 60C while my 9300M in my Asus U6V idles at 49C and even my 9800M GS in the Asus G71G idles at 60C.

Has anyone else seen these metal-foams used in other laptops and do you think this decision of using foam heatsinks is due to lower production costs? I personally would have preferred solid copper/aluminum w/ thermal paste rather than a piece of foam What do you guys think?

Top red circle = chipset heatsink; lower right red circle = GPU heatsink


Close up on GPU heatsink

 

Yep, thermal contact for the GPU is a piece of crap. I've hit load temps of up to 100C on the Quadro with that thermal pad. Copper-modding it properly brings the load temps down into the low 80s, idle temps into the low 50s. On the other hand, stock NB temps never get that high; I've never gone above 60C, so the thermal pad seems to suffice there.

 

This is such a shame; being a business class notebook that should have superior components over standard consumer notebooks, this was definitely not what I expected from a new Latitude. While typing this post and not performing any other tasks, my GPU has jumped to 71C.

 

ouch. on a side note, i've seen this foam stuff on my m15x' heatsink as well, but only over the memory modules around the side... the chip itself is "connected" to the copper heatsink plate by thermal grease.

 

I have this model and the Quadro GPU, and my idle temps are around 51º. Guess I was lucky? (btw this was bought in the EU)

 

I would assume they used foam because it works, it's lighter, and it's less expensive to design, build, and apply. If one unit is running hot, can you just assume it's the foam?

GK

 

There could be other reasons that a unit is running hot ... anything from high ambient temps to dust in the heatsink. And of course some units will naturally run hotter or cooler than others. The thermal pad is just another gear in the system, and one that's a bit harder to fix/change at that.

The thermal pad has really been the standard GPU/heatsink connector for a long time now. I saw it in my D600 and my D830; it's flaws are only becoming more recently evident because the GPU is starting to dump a lot of heat these days.

I do believe (and this is a 100% guess, just FYI) that one of the reasons for using a thermal pad is the balance of the heatsink. If there is solid metal at all three heatsink contact points, CPU, GPU, and NB, depending on the varying heights of the three chips (which may be inconsistent due to soldering or whatnot), the heatsink could tilt, which would cause one, if not all of the three chips to have very poor thermal contact with the heatsink.

Dell must have decided that this would happen a bit too often with an all metal-to-chip thermal solution and opted only for direct contact on the part with the highest TDP.

 

Yes, I know on the Asus C90S, they use the same foam but only on the video memory modules too.

You're right, it could also be a faulty GPU. That's why I'm trying to get other owner's input as well.

As for ambient temps, I purposely left my window open last night while I left my laptop running. My room temp was at steady 50F (10C) this morning, and the GPU was idling at 65C

 

My NB temperature rarely go above 50C, because if it does, the fan starts spinning at the annoying full speed mode (4800 RPM) and it brings down the temperature. Do you have the fan running at full speed a lot? I really would have liked to have better thermal contact for the NB to keep its temperature a few degrees cooler because then the fan would not have to run at full speed even if it is warm temperatures in house like in the summer.

In the service manual for D830 it looks like the heatsink for the GPU is a separate piece screwed to the motherboard. It also have its own heatpipe. See http://support.euro.dell.com/support/edocs/systems/latd830/en/SM_EN/cpucool.htm .
On D630 (with integrated graphics) it looks like the NB has its own heatpipe. See http://support.euro.dell.com/support/edocs/systems/latd630/en/SM_EN/thermal.htm .

All in all, the cooling system on D630/D830 looks a little bit larger than on E6400/E6500. Sharing the heatpipe for all hot parts like in E6400 seems to be a bit strange.

Are the temperatures of GPU and NB lower on D830?

Örjan

 

I also believe that removing the thermal pad makes it much less effective when you put it back on. That could explain an increase in temps if you removed the heatsink.

Greg