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Khenglish

[HARDWARE MOD] P150EM VGA core radiator 50% more fins

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So I noticed that radiators my ancient inspiron 8000 and 8200 had a substantially higher fin density than those on my P150EM. I bought a spare VGA heatsink from SVL7 for very cheap a while back and figured that I'd add some of its fins to my radiator and see what happens. If it made things worse, then I had a reason to buy the SM series heatsink. The idea is that this is a trail run for redoing the CPU radiator, since my VGA temps are fine, but CPU temps could use some work when it's drawing 75W+

The final result (not foiled. foiled it after this pic):

http://i.imgur.com/25UQOeb.jpg

The unmodified radiator has 65 usable fins (no air blows through 2 of them). I now have 96 usable fins. I didn't bother making the tiny fins on the end more dense since they're tiny and probably hardly do anything.

The net result is a 6C temp improvement. Temperature testing was done in unigen valley. With a 70.4F room temp full-speed fans resulted in 78C max temp with the 7970m at 1.1V core, 1.6V mem 1060 core/1575 memory. After this mod at the same room temp it only hit 72C. Automatic fan speed was 87C max, and now is 82C max. I heard that the SM series heatsink runs roughly 8C cooler than the EM series heatsink, so I was close, but I have better voltage regulation and memory cooling for my 2C higher core temps.

You probably saw the oddly placed extra heatpipe on my 7970m heatsink. I put it there because with all my overvolts, I was getting crashes due to voltage regulation overheating. That extra heatpipe brings the heat from the inductors and FETs to the memory heatpipe. Adding this heatpipe got me around 15Mhz more on my core. I'm still down around 10MHz on the core from what it can do with no memory overvolt, but -10MHz core for +80MHz (320 effective) on memory is well worth it. The heatpipe does fit with the bottom cover on.

This mod was an incredible amount of work. Getting the fins consistent is not trivial. I threw away around 20 fins due to sanding them unevenly. The ones I used are not perfect, but they were good enough for an improvement.

I was hoping for more than a 6C improvement with a 50% bigger radiator. Air flow is noticeably down. It seems that I made the fins slightly too dense, and an increase of around 33% is probably best. I will go for that ratio when I do the CPU radiator.

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How did you added the fins?

Aren't those supposed to be soldered to the heatpipes?

Sent from my iPhone using Tapatalk

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How did you added the fins?

Aren't those supposed to be soldered to the heatpipes?

Sent from my iPhone using Tapatalk

Toaster oven at 375F takes care of that. The annoying part is that they are individually hooked together with the the fins on either side. It takes a while using a pin to undo all the hooks.

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Ok. So oven to desolder.

Now how to solder them back, including the new added slices of copper?

Also, is there any danger to blow the heatpipes? i assume if I overheat them too much they will eventually blow...

Sent from my Nexus 4 using Tapatalk

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Yes heatpipes do pop if you overheat them. They will start to expand at around 400F (they will unflatten), and blow up around 500F.

I used fins from my existing radiator as well as one I bought for cheap from svl7. I put the fins back on using 63/37 solder paste.

I am taking pictures of the process on the CPU radiator. So far the project is proceeding very well with 23 fins done.

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They have some gas/liquid under pressure that when hot is in gas form, when cooled down they return to liquid state. If blown, they won't cool much.

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