Author Topic: System Power Requirements and Cooling solutions. (Read 6264 times)

[BTF]Sigma · « **on:** October 25, 2009, 07:34:33 PM »

I'm picking up a EVGA GTX-260 tomorrow. (md#:017-P3-1165-AR)

I have a 520W PSU and the guy at the store thought that having a 600W supply would be better.

I am running:

Acepower 520W PSU
Asus P5Q Mobo
EVGA 8600 GT SC
Intel Core 2 Quad Q8400 2.66gHz

I really know nothing about power requirements and am asking the tech gurus here if adding this new card would require more power to my system.
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Second part is the cooling solutions/heat management. My current gfx card gets pretty hot during heavy workload mainly because it's a factory overclocked model. I thought it would be fine on it's own with a two fans leading out and one going in to the case. The two exhaust fans are one on the side of the case centered on the gfx heat sink and the other placed just below the PSU. The intake is on the front of the case located on the bottom edge. With that I thought I would have ample air flow to dissipate the heat but when I opened the case after having the system blue screen and ram dump before restarting I found my GFX card to be really hot, like don't keep your finger on the heatsink(so much so that it made the warranty sticker on the other side of the card had actually curled up and the glue had stuck to the circuit board. :/ )

Are there certain fans that are better than others? Are there specific concepts to keep in mind when trying to get rid of hot air.

R1CH · « **Reply #1 on:** October 26, 2009, 12:29:40 AM »

Never heard of Acepower, but you need to ignore the Wattage rating and look at the amps, many manufacturers will give you a high Watt rating but if all the amps are on the 3.3v rail and all your system components need 12v (like GPU does), then your PSU will not be good enough. Look on the side of the power supply for something that should say how many amps it has for each voltage, the +12v is the main number to look at, you'll want at least 35A on the +12v.

[BTF]Sigma · « **Reply #2 on:** October 26, 2009, 07:18:48 AM »

Just checked it.

35A on the +12v rail.

So it's good?

Whirlingdervish · « **Reply #3 on:** October 26, 2009, 09:00:02 AM »

if you arent runnin a ton of HDs and optical drives on that same rail, you should be good.

[BTF]Sigma · « **Reply #4 on:** October 26, 2009, 09:11:00 AM »

Just one HD and one dvd-r. Not sure if it's all on the same rail. I'll try to look up how to figure it out when I get home today.

Any tips on heat management? The pedestal fan lying on the ground next to my pc is getting a little loud.

Whirlingdervish · « **Reply #5 on:** October 26, 2009, 10:09:06 AM »

lots of case fans, and some form of intelligent design when it comes to their placement.

generally you'll want to create a sort of wind-tunnel with a fan or two in the front pulling air and a fan or two in the back expelling hot air after it passes through your cpu cooler and vid card fan/heatsink.

a lot of cases (atx and atx mid) will have a vent on the lower part of the face that's meant to draw cool air, and often there's a bracket there or some holes for mounting an 80mm fan.

depending on the case, you could always customize the side door to accept another fan if there isn't room elsewhere.
this doesnt promote the best airflow, but sometimes you just need to get some shit blowin in there even if you cant get the angles just right.

[BTF]Sigma · « **Reply #6 on:** October 29, 2009, 10:27:35 AM »

So it works. Had a couple extra fans put in. Ran crysis, ut3, farcry2 all silly smooth at full detail at 1680x1050. Nerdgasm.

Pr0c3550r · « **Reply #7 on:** October 29, 2009, 01:20:01 PM »

From an engineering point

#1 negative pressure in a box is best , suck the air OUT.

#2 There is a chart that shows the balance between CPU / MB Performance and Power supply.

Peace

R1CH · « **Reply #8 on:** October 29, 2009, 09:32:08 PM »

You want positive pressure in a case or you will suck in dust through all the tiny gaps.

QwazyWabbit · « **Reply #9 on:** October 29, 2009, 10:10:40 PM »

As Rick said...

Positive pressure is best.

Air should be filtered at the fan inlet and fan power should be suited to give rated air flow with the addtional restrictions of the filters or screens in the air path. Negative pressure allows dust and contaminants into the cabinet via the joints and cracks and other imperfections of the enclosure. A simple fiberglass mesh works well for SOHO environments and can be replaced or cleaned easily when externally mounted. Positive pressure moves cleaned warm air out via the enclosure gaps helping to keep dust out.

Industrial enclosures often use air conditioners or often simple heat exchangers to circulate interior air across a heat sink mated to an external heat sink with exterior fans. This is usually enough to allow the interior air to dump waste heat to the outside without exchanging air. A separate means of maintaining positive pressure is needed in extreme cases.

I once had to go to extreme measures to keep graphite dust out of an industrial enclosure to keep the dust from blowing out a power supply every six months. Filtered, dried, shop air at 7 PSI was needed along with air conditioning to dump the waste heat. It took a week of cleaning and filtering to decontaminate the cabinet but once it was cleared the problems went away.

[BTF]Sigma · « **Reply #10 on:** October 30, 2009, 08:11:07 AM »

So pump a crap load of air into the case from a filtered source and let the cards on board fan handle the cooling or should I try to get a conditioned source before the fan intakes?

I was thinking of picking up the Antec900 case to house everything as it seems to have enough fans to power a coast guard hovercraft.

QwazyWabbit · « **Reply #11 on:** October 30, 2009, 09:33:45 AM »

Use a fan system that can pull more filtered outside air into the case than the other fans that might push out. This will keep positive pressure inside. The extra air will find it's way out the gaps in the case. The added pressure has the effect of increasing the air density, this improves thermal conductivity of the air but the effect is slight. This pressure effect is why there are operational altitude constraints on equipment.

Fans directing air onto the heat sinks are recommended. The goal is to keep the heatsinks as close to ambient as possible. There is a trade-off of air flow and it's temperature and the heatsink and its temperature. When the air flow is high it is in contact with the heatsink for a shorter time and doesn't get as warm. The airflow should be sufficient to displace the warm air away from the heat source but not so fast that the molecules don't have enough time to be in contact with it and pick up the heat. Too fast means you are expending fan energy and making noise for no benefit. Slower air means it comes off at higher temperature but with more T-rise in the heatsink.

ASICs and CPU/GPUs run hot. The dies are typically at 90 to 120 C with the heatsinks pretty close to the same temperature if they are doing their job effectively. 90 C is 194 F and you will blister your finger on that one. Generally, if you can keep your finger on it for more than 3 seconds it's below 125 F. Save your fingers and get an infrared pyrometer, a Fluke 62 mini works well (US$ 100), to get heat sink temperatures. Proper air flow will put the fin tips at ambient plus 5 or 10 degrees with the overall average heatsink temp at ambient plus 20 C.

Generally, the more air the better, this keeps the heatsinks dissipating the power into the ambient air. How much air you desire depends on your fan noise tolerance. A good thermal monitoring system (like CPU and GPU thermal diodes and software to monitor them) will tell you what your thermal design is doing. Heat is the enemy, anything you do to keep the thermal rise of the chips at a minimum is good. The important factor is the temperature rise of the chip from ambient, the smaller the better. Noise should be less than a 747 at takeoff. Liquid cooling systems are the solution when fan noise is a consideration.

[BTF]Sigma · « **Reply #12 on:** October 30, 2009, 11:43:24 AM »

Great advice Quazy.

Dayum....I wish I had your job/knowledge. I'm beginning courses @ BCIT Let's see if I can find something great in their IT sector.

The gfx card has it's own fan intake on the card and an outtake which takes up an extra expansion port to vent out the heat produced by the card. Please see image attached

Below the card there are 4 access panels available (the fourth being used by an external firewire/sata adaptor.

My initial thoughts are to mount an intake fan that will drive air into the case and towards the gfx card's intake fan and using the HDD cable as a path shaper to ensure that maximum flow is available.

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What case and airflow solution do you recommend for someone who wants to stay on the curve of game development for the next 5 years. I will be upgrading my components as needed.

(ps. I sincerely appreciate all the input. This is a great learning experience for me.

)

[BTF]Sigma · « **Reply #13 on:** October 30, 2009, 12:29:56 PM »

Uh oh...looks like I posted another p-p-p-p-pagebreaker!!!

QwazyWabbit · « **Reply #14 on:** October 30, 2009, 01:45:46 PM »

Five years? Yikes, the market turns over every 6 months.

Cases are pretty much the same in the ATX class. You could use a big tower with a 10-drive capability and have lots more room for fans but I am not sure they still make them.

I am not sure which direction that fan at the top of the image flows but my guess is that it's flowing up, into the fan (power supply?). In that case your grill on the left is in a bad place from the standpoint of getting good air exchange and circulation through the rest of the case.

Air will flow like a fluid and take the path of least resistance so you want the low mass, low resistance path to cross the area around the GPU or else you want to help it along as you suggested with a duct and another fan. You might want to install a ducted fan in that empty grill and duct the air into the lower part of the case to get lots of air displacement in that region.

Author Topic: System Power Requirements and Cooling solutions. (Read 6264 times)

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