R7 250 custom cooling

[AlexKV]

Hello all, I'm new to this forum, new as a member but reading it for a long time.

I have some spare time and Asus R7 250 graphics card that I want to make a new air cooling for. The reason for that is a very crappy factory cooler which doesn't just sound awful, but started to sound "loosened" at it's shaft, making clicking sound at it's default 40% speed.

I've been modding coolers on some graphics and processors before, but this time, I was wondering if I could go for 0 db (no fan).

So my question is: how does big aluminum block work as a heatsink? I have some aluminum plate which is about 12mm thick, so I was thinking of putting lots of metal mass so it will compensate for the fan.
Also, I guess it would make it more "inertial" as it would heat/cool much slower than small fan blown with fan which now cools from 80c to 30c in 30 seconds.

One more thing: Do parts (marked on picture) need a heatsink? They don't have heatsink now but the fan blows over them for sure.



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Forgot to mention, after installing a big CPU heatsink over the GPU chip and fan which wasn't blowing other parts of the card, the monitoring software was reading 50c at idle and going over 100c easily while at load. Does the temperature sensor measure any other part?

 

[ATMINSIDE]

You most likely weren't getting enough pressure with the CPU cooler on the card.
Did you check Arctic Cooling to see if they make a cooler?

 

[AlexKV]

There are additional coolers to buy, but I want to make one as I like to make things.

Maybe there wasn't enough contact pressure, but even if it has enough pressure and main GPU chip is properly cooled, can any other part get overheated if fan is not blowing on them?

 

[bob4933]

Green circles should have a heat sink, blue circles need airflow.

As far as just slapping a chunk of aluminum on it, Im unsure. One thing you can try (mind you this is on you), take the plastic cover off and remove the fan and try to run it passively. Obviously watch temps like a hawk.

http://www.amazon.com/Cosmos-Copper-Cooling-Heatsinks-cooler/dp/B00637X42A

 

[AlexKV]

Green circles (VRAM?) don't have heatsinks. There's a factory heatsink going over them, but there is a ~1mm gap, so air flows over them.

About chunk of aluminum... it would be a big chunk, but i would also place a cpu cooler on top of it... Running a factory heatsink passively isn't possible, already tried, and it heats too much so only light web browsing is possible, without watching videos.

 

[ATMINSIDE]

Sounds like you don't have enough case airflow to me

 

[bob4933]

I would recommend a larger fan than a "chunk of aluminum". Larger fan can operate at lower rpm for the same amount of air flow and cooling as the smaller fan. Getting directed air flow would be the crux of it I suppose.

The 250 is a lower powered chip, but typically, the vram needs cooling with a passive heat sink at the least. It probably is fine with the direct airflow, but if youre gonna mod it, I'd just "do it right" so to speak.

 

[AlexKV]

Already tried the bigger fan, even the noisy one with 2500rpm. The plastic covering the gpu and holding the fan in place is actually working as some kind of spoiler, directing the air to blow on whole side of the card. By placing various fans instead of it (without plastic), it just had higher temperatures. That's why I want to try more massive heatsink...

 

[bob4933]

A half inch bar of aluminum isn't going to be much of a heat sink really. Its not just the mass, its the surface area for cooling. A block of aluminum has almost no surface area compared to a finned cooler. The aluminum thats already on there will most probably have a huge amount of surface area compared to the block you're trying to do.

Also, with no air flow, your vrm and memory are going to over heat as well, you still need a fan.

 

[AlexKV]

I understand all of that, and maybe I didn't explain well, but the half inch aluminum plate isn't going to be the only part, i would attach one CPU cooler on top of it, and one big transistor cooler at the side, which is perfect for passive cooling.

Other thing I didn't mention: the GPU chip itself is about 1.7mm rised from the pcb, while vrams are about 0.9mm high, so if I put an aluminum plate on top of them, there would be a gap of about 0.8mm. Which type of compound would be the best to fill that gap? Thin thermal compounds as Cooler Master E1 wouldn't be the best, but there is some kind of cheap heatsink plaster that I have which is quite thick like a toothpaste and glues the heatsink and becomes pretty hard, but also pretty hard to remove, and there are thermal pads used to stick small heatsinks designed for vrams, will those work better?

 

[ATMINSIDE]

You use thermal pads, not paste, for a gap.

 

[bob4933]

I understand all of that, and maybe I didn't explain well, but the half inch aluminum plate isn't going to be the only part, i would attach one CPU cooler on top of it, and one big transistor cooler at the side, which is perfect for passive cooling.

Other thing I didn't mention: the GPU chip itself is about 1.7mm rised from the pcb, while vrams are about 0.9mm high, so if I put an aluminum plate on top of them, there would be a gap of about 0.8mm. Which type of compound would be the best to fill that gap? Thin thermal compounds as Cooler Master E1 wouldn't be the best, but there is some kind of cheap heatsink plaster that I have which is quite thick like a toothpaste and glues the heatsink and becomes pretty hard, but also pretty hard to remove, and there are thermal pads used to stick small heatsinks designed for vrams, will those work better?

No you explained fine. Adding in a half inch plate of aluminum will not do very much for you. The lack of surface area, and relatively high specific heat capcity and low thermal conductivity (compared to copper in any case) means it wont be very effective as a heat sink. Once it heat soaks it will become completely useless. Wouldn't shock me to see temps rise honestly. You're much better off just using the cpu cooler alone. Using a large enough cpu cooler with heat sinks on the ram will probably let you run the card passively. That combined with proper case air flow will probably work quite well.