How important is a good exhaust fan?

[norulezapply]

Hi guys.
I'm running a mining rig at the moment with 2 cards, fans at 80% and temps at about 72C.
It's a basic case with a 120mm fan at the front, pulling air in, and an 80mm fan at the back, exhausting air out, along with the PSU.
The fans are very cheap (eBay quality) so I've recently ordered a better 120mm fan to replace the front intake fan, which should hopefully help my temperatures.

My question is should I upgrade my 80mm fan to a stronger one too?

The reason I ask is because I've noticed there's a fair bit of hot air also being exhausted through the PSU and I don't want to risk blowing my PSU through not properly cooling it or anything.

Thanks

[1714190726]

1714190726

[1714190726]

1714190726

[xunker]

With two cards, if you're getting a lot of heat from the PS and no heat from the other exhaust fan then the heat you're feeling coming out of the PS could actually be FROM the PS.

Do you know the quality of the PS?  Is it a "cheapie" or something more premium?  I ask because cheap power supplies have pretty sucky efficiency ratings, so the more power your system needs to more heat your PS generates.  It you're using a budget PS I'd definitely consider upgrading to a more premium PS with dual fans and/or "80 PLUS Certified" at least (80 PLUS Gold/Platinum is better, but more expensive).

[norulezapply]

With two cards, if you're getting a lot of heat from the PS and no heat from the other exhaust fan then the heat you're feeling coming out of the PS could actually be FROM the PS.

Do you know the quality of the PS?  Is it a "cheapie" or something more premium?  I ask because cheap power supplies have pretty sucky efficiency ratings, so the more power your system needs to more heat your PS generates.  It you're using a budget PS I'd definitely consider upgrading to a more premium PS with dual fans and/or "80 PLUS Certified" at least (80 PLUS Gold/Platinum is better, but more expensive).

The heat is coming out of both fans because there's a lot of heat built up in the case from the GPUs.
The PSU is a new GX 650w from cooler master. Not the best quality but it's never usually hot so I assume the heat is just heat from the GPUs. I believe that PSU is 80+ Bronze certified. Is that any good? I was on a bit of a budget. I don't want to spend a year paying off my rig so I didn't really want to spend a lot of money.

EDIT: Although I really want to buy another GPU but I feel uneasy about whether i'll be able to pay it off or not.

[Sannyasi]

you can only blow as much air out as you are taking in- if you have more fans doing one or the other you'll still benefit from the air movement but it will be poorly optimized. A general rule of thumb for regular case layout (PSU on top) is to have intake fans on the bottom/front of the case and have exhaust on the top/back- this lets hot air rise from the case without being sucked back in. I've tried alot of combos of fan placements and it can make a huge difference on your temps if done wrong/right. hope this helps

[norulezapply]

you can only blow as much air out as you are taking in- if you have more fans doing one or the other you'll still benefit from the air movement but it will be poorly optimized. A general rule of thumb for regular case layout (PSU on top) is to have intake fans on the bottom/front of the case and have exhaust on the top/back- this lets hot air rise from the case without being sucked back in. I've tried alot of combos of fan placements and it can make a huge difference on your temps if done wrong/right. hope this helps

Thanks for the tips. Unfortunately the case is laid horizontally so that screws up the airflow a bit, any tips for this setup?

[SMOKEU]

Get a jigsaw and cut holes in the side of the case (in your case the "top" of the case) and mount 2 X 120mm fans blowing air directly onto the video cards. Keep in mind that most 120mm fans are about 25mm thick so make sure that your case has enough clearance to do it. Don't forget the dust filters either.

I did that to my case and it made about a 5 - 7°C temperature reduction, especially on the top video card. I would still recommend that your case has a slight positive air pressure inside it rather than a vacuum, because if you have a vacuum inside your case then it's likely to be sucking in unfiltered air.

[norulezapply]

Good idea. I was considering that but didn't think it was necessary. Should I have dust filters on all of my fans? I didn't think they were necessary either to be honest.

[Sannyasi]

the suggestion above is a good one- that's the first place i'd add a new fan if mining with a closed case (i have the side of my case off with a house fan handling things). For a side sitting case I'd guess the best place for exhaust fans would be near the PSU, but i've never tinkered with airflow on a side sitting case so i don't have experience in the matter.

[xunker]

GX 650w from cooler master.

CoolerMaster is good, definitely not the cheap crap you find in bargain-basement PCs.  It's a name that has been around for a while.

[Tim the Magician]

I usually focus on a lot of input fans and let a combination of the video card exhaust fans and passive vents handle the output.  If you have a lot of air coming into the case you will have a lot of air coming out..  The cases I'm using now I have 3x 120mm + 2x 180mm input fans and only a single 120mm output (near the CPU) + all the video card fans and some passive vents.

If you can get a high air flow for your intake fan it could help to add vented slot covers for the expansion slot covers between the cards (or just remove the slot covers) this can help remove some of the hot air from around your cards.

Silverstone vented slot covers:


I agree with the adding fans in the side panel blowing into the card intakes.

Also pay attention to cable clutter within your case.. try to eliminate or reroute cables which may block airflow.

Higher grade power supplies usually have modular cables which can be removed if not needed helping improving airflow in addition to the power savings from the higher efficiency.

[norulezapply]

GX 650w from cooler master.

CoolerMaster is good, definitely not the cheap crap you find in bargain-basement PCs.  It's a name that has been around for a while.

Good to hear this! I've heard a lot of people slating the PSU for being a cheap rip off, but it seems like a fantastic mid-range PSU to me, so I'm glad someone agrees!

I usually focus on a lot of input fans and let a combination of the video card exhaust fans and passive vents handle the output.  If you have a lot of air coming into the case you will have a lot of air coming out..  The cases I'm using now I have 3x 120mm + 2x 180mm input fans and only a single 120mm output (near the CPU) + all the video card fans and some passive vents.

If you can get a high air flow for your intake fan it could help to add vented slot covers for the expansion slot covers between the cards (or just remove the slot covers) this can help remove some of the hot air from around your cards.

Silverstone vented slot covers:


I agree with the adding fans in the side panel blowing into the card intakes.

Also pay attention to cable clutter within your case.. try to eliminate or reroute cables which may block airflow.

Higher grade power supplies usually have modular cables which can be removed if not needed helping improving airflow in addition to the power savings from the higher efficiency.

Thanks for the fantastic reply. This was exactly what I was hoping. I'm temporarily running caseless until I get my new 120mm Scythe Kaze Jyuni. Anyone know if this fan is any good? http://www.ebay.co.uk/itm/330601649625