Too hot passive VGA card. Need a fan somewhere.

jeremia.morling · Aug 1, 2010

Hi!
I'm trying to make a silent PC.
I bought a PowerColor HD 5750 SCS3 with only heatsink, no fan. The problem is that it gets to hot (104 degrees C in FurMark). I will by a new fan, but I am not sure what. I currently only have 1 case fan at the top back blowing air out of the case (Noctua 120 mm)
Here are my alternatives:
1. Noctua Case fan 92 mm: Mount on lower front for air intake.
2. Some kind of fan mounted directly on the VGA heatsink. Which fan should I use?
3. Some case fan: Mount on the side (there are holes, but not for mounting a fan, maybe 120 x 80 mm) or on lower back (removing non used slot covers).

If I do option 2 or 3 I could make cardboard thing to lead the fan air directly from outside the case to the heatsink.

What do you guys suggest?
/ Jeremia

CompuTamer · Aug 1, 2010

The Scythe Gentle Typhoon is a good fan. Moves a good bit of air very quietly.

I think if you put a fan in the front of the case, that would blow air over the GPU heatsink. There's probably just not any airflow near the bottom of the board, so it's getting hot.

psionic98 · Aug 1, 2010

what kind of system are you running.. cause 1 fan in general isnt a good idea.. at least 2 for some proper cross-flowing air is best imo.

if you can stand a little noise, id gow ith option 2 & 3. for 3 id go with a yate loon low speed or scythe gentle typhoon.. they are pretty silent and move enough air just to stir things up

and :welcome:

to the forums!!

for 2 id go with a small 60mm fan, but you'll want to get an external fan controller for it (they make singles that take up a pci port on the back of the case) and turn it down a little as they tend to get noisy at 100%

Bobnova · Aug 1, 2010

What CPU, cpu cooler, case, and power supply?

What i would do is thusly:

I would seal all the intake openings except one (note: this MUST have as much open surface area as your exhaust fan does, or very close to it, or more). That one i would duct so that all the intake air must flow over the GPU heatsink.

I would then duct the exhaust fan so that all the air it pulls in has to come through the CPU heatsink first.
Alternatively, put the fan on the cpu heatsink and duct the hot air that comes out of the cpu heatsink to the outside of the case, the CPU heatsink then acts as a muffler to fan noise.

Presto! If the fan is a halfway decent one it can move enough air to keep both the low power GPU and the CPU cool.

EDIT:
That said, unless you're going to be crunching milkyway@home or somesuch, nothing is going to even come close to furmark loads.

2.EDIT:
The key IMO is not the standard issue MOAR AIRFLOW! that is generally preached, but carefully sculpting the airflow you have. My favorite setup so far had one 1000rpm intake fan, a similar cpu heatsink fan and another on the gpu heatsink, plus a power supply with a 140mm fan that turned a good 350rpm under heavy loads. You could barely hear it if your ear was within 6" of the case. The key was ducts, all the cpu heat went out of the case directly.

m0r7if3r · Aug 1, 2010

Bobnova said:
What CPU, cpu cooler, case, and power supply?

What i would do is thusly:

I would seal all the intake openings except one (note: this MUST have as much open surface area as your exhaust fan does, or very close to it, or more). That one i would duct so that all the intake air must flow over the GPU heatsink.

I would then duct the exhaust fan so that all the air it pulls in has to come through the CPU heatsink first.
Alternatively, put the fan on the cpu heatsink and duct the hot air that comes out of the cpu heatsink to the outside of the case, the CPU heatsink then acts as a muffler to fan noise.

Presto! If the fan is a halfway decent one it can move enough air to keep both the low power GPU and the CPU cool.

EDIT:
That said, unless you're going to be crunching milkyway@home or somesuch, nothing is going to even come close to furmark loads.

2.EDIT:
The key IMO is not the standard issue MOAR AIRFLOW! that is generally preached, but carefully sculpting the airflow you have. My favorite setup so far had one 1000rpm intake fan, a similar cpu heatsink fan and another on the gpu heatsink, plus a power supply with a 140mm fan that turned a good 350rpm under heavy loads. You could barely hear it if your ear was within 6" of the case. The key was ducts, all the cpu heat went out of the case directly.

damn, that sounds absolutely awesome, you got a pic of that?

as for op, any airflow over the gpu has got to be better than what you've got now, so the approach I would take would be an ultra low speed on the side of the case blowing right on the gfx, it'll keep the hot air from building around the gfx and essentially reduce your ambients by helping to equalize the temps in your case.

Bobnova · Aug 1, 2010

There were two iterations, this was the first, it had the cpu fan and gpu fan ducted to be intakes (so they got room temp air, not warm case air), then a 120mm 1000rpm exhaust.

Can't find my pic of the other setup, donno where it went. It was pretty ghetto too

m0r7if3r · Aug 1, 2010

That one on the side goes to the graphics card, right?

CgS Drone · Aug 2, 2010

What was happening with your board temps Bob? I can see where you are trying to draw fresh air in to cool the cpu and vid card but that is leaving only the heated air by the vid card and cpu to cool the rest of the board and hdd's unless there is something I am missing???

m0r7if3r · Aug 2, 2010

psu fan might be movin enough air to keep it reasonable...

Bobnova · Aug 2, 2010

SB had a fan cause it didn't have a heatsink, the NB and vrms were cooled by the downdraft of air coming out of the cpu heatsink.

jeremia.morling · Aug 2, 2010

The Scythe Gentle Typhoon is a good fan. Moves a good bit of air very quietly.

I think if you put a fan in the front of the case, that would blow air over the GPU heatsink. There's probably just not any airflow near the bottom of the board, so it's getting hot.

The only Scythe Gentle Typhoon I could find here in Sweden seems to be 120mm. I the max size for my front fan is 92mm.

what kind of system are you running.. cause 1 fan in general isnt a good idea.. at least 2 for some proper cross-flowing air is best imo.

if you can stand a little noise, id gow ith option 2 & 3. for 3 id go with a yate loon low speed or scythe gentle typhoon.. they are pretty silent and move enough air just to stir things up

and welcome to the forums!!

for 2 id go with a small 60mm fan, but you'll want to get an external fan controller for it (they make singles that take up a pci port on the back of the case) and turn it down a little as they tend to get noisy at 100%

Thanks for the welcome!
I only had one fan previously because I only neeeded one fan.

What CPU, cpu cooler, case, and power supply?

What i would do is thusly:

I would seal all the intake openings except one (note: this MUST have as much open surface area as your exhaust fan does, or very close to it, or more). That one i would duct so that all the intake air must flow over the GPU heatsink.

I would then duct the exhaust fan so that all the air it pulls in has to come through the CPU heatsink first.
Alternatively, put the fan on the cpu heatsink and duct the hot air that comes out of the cpu heatsink to the outside of the case, the CPU heatsink then acts as a muffler to fan noise.

Presto! If the fan is a halfway decent one it can move enough air to keep both the low power GPU and the CPU cool.

CPU: E7400, CPU cooler: ThermalTake Sonic Tower (passive), case: cheap tower, PSU: Corsair 450W.

I like what you are saying. Here is a picture of my computer:

I think I will buy a Noctua 92mm fan running at slow speed and place it at the front and duct it so that all air will blow at the VGA side facing to the front of the computer.
If I do that I have 2 options more:
1. Duct the way out for the air as well through the removed slot covers so I will have an air tunnel only for the VGA heatsink.
2. Even duct the bottom end of the VGA heatsink in order to force all air to move through the whole heatsink.

What do you think?

There is an air intake (no fan) at the side directly above the CPU heatsink, so it can have its own airflow with the top case fan blowing out. I think I will cut away all metal in front of the fan so that it will have more free airflow.

Thanks for your help! :thup:

Elfie · Aug 2, 2010

Depending on the design of the heatsink you could zip tie a fan to it. I've done that with my HD4350 and have it barely spinning but it's enough to keep it at reasonable temperatures.

jeremia.morling · Aug 2, 2010

Elfie said:
Depending on the design of the heatsink you could zip tie a fan to it. I've done that with my HD4350 and have it barely spinning but it's enough to keep it at reasonable temperatures.

Yeah, I just went to rest after writing my previous post and I just thought that:
Buy a 140 mm case fan, strap it onto the VGA heatsink directly. Cut away the metal between the slot covers at the back and make an intake airtunnel from the now open back to the fan. That would be even better. Slow spinning and quiet.

Elfie · Aug 2, 2010

You should be able to zip tie a 120mm on that and the Scythe Gentle Typhoons run without a 'ticking' noise at slow speeds. You may have difficulty fitting a 140mm fan on it as the zip tie pressure tends to skew the fan to a central position and overhangs the back of the card and makes it difficult/impossible to get the card in the slot.

jeremia.morling · Aug 2, 2010

Elfie said:
You should be able to zip tie a 120mm on that and the Scythe Gentle Typhoons run without a 'ticking' noise at slow speeds. You may have difficulty fitting a 140mm fan on it as the zip tie pressure tends to skew the fan to a central position and overhangs the back of the card and makes it difficult/impossible to get the card in the slot.

Why not use a Noctua NF-S12B FLX 120mm instead?
It says 6.2 dB @ 600 rmp, 29.52 CFM

Scythe Gentle Typhoon 120mm 500rpm:
5 dB @ 500 rmp, 18.25 CFM

The Noctua fans seems to have better airflow for similar noise-level.
Why do so many think that Scythe Gentle Typhoon is the fan to choose?

Elfie · Aug 2, 2010

Slightly biased because I use the GT's on my Rad's in 3 systems. They have higher static pressure which doesn't matter as much for case/graphics card fans. I do know the higher speed Noctua's can 'tick' at low speeds but if you buy a low speed one to start with then it won't matter. Noctua tend to exaggerate performance a bit.

ratbuddy · Aug 2, 2010

104 in Furmark is nothing to worry about for a passive card. How hot does it get during actual games? If it's 90 or less, just let it be, no worries :beer:

Bobnova · Aug 2, 2010

jeremia.morling said:
I think I will buy a Noctua 92mm fan running at slow speed and place it at the front and duct it so that all air will blow at the VGA side facing to the front of the computer.
If I do that I have 2 options more:
1. Duct the way out for the air as well through the removed slot covers so I will have an air tunnel only for the VGA heatsink.
2. Even duct the bottom end of the VGA heatsink in order to force all air to move through the whole heatsink.

What do you think?

There is an air intake (no fan) at the side directly above the CPU heatsink, so it can have its own airflow with the top case fan blowing out. I think I will cut away all metal in front of the fan so that it will have more free airflow.

Thanks for your help!

I like this plan.
You should check the NB and SB temps to make sure they're getting enough airflow as well, if you can touch the heatsinks without getting burnt they're ok. Ideally you should be able to leave your finger on 'em without any pain.

jeremia.morling · Aug 2, 2010

120 mm fan on VGA heatsink decided

ratbuddy said:
104 in Furmark is nothing to worry about for a passive card. How hot does it get during actual games? If it's 90 or less, just let it be, no worries

That is when I run my current case fan at full speed, which is not a good option since the high airflow through the CPU cooler and out through the case makes a lot of noise.

I will buy another Noctua 120mm fan and strap it directly on the VGA heatsink. Then make an airtunnel from the back and maybe the side of the case to get room tempered air into the fan.

The main reason for choosing this alternative is that I had a Noctua 92 mm fan at the front for some time and it was too noisy even at low speeds. Plus the air intake at the front is not so good. Only a small area at the bottom of the front cover. The only bad thing with this solution is that the hot air from the VGA heatsink will blow into the case, but I think it will be ok.

Thanks for all your help!

jeremia.morling · Aug 13, 2010

Just to close this thread

I bought a Noctua NF-S12B ULN (120 mm) running at 640 rpm and attached it to the VGA heatsink. I ducted the air intake to get room tempered air for the fan.
The noise increase was almost none and the temp in FurMark dropped from 104 C to about 86 C. I overclocked the GPU (700 MHz -> 750 MHz) and VGA memory (1150 MHz -> 1200 MHz) slightly with maybe 1 C temp increase.
I also removed all metal in front of my original case fan. Here are pictures:

Thanks again for all your help!

Too hot passive VGA card. Need a fan somewhere.

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