Question on heat dissipation

Question on heat dissipation

I have an ASUS Mother board a M4A78T-E and I have now added the 6850 Sapphire Toxic edition x2 in cross fire. I was playing Dirt 3 last night on max settings in 1080 on a monitor. I have never played it before but it came free with the new video card and the graphics are pretty good. Everything is running great on my pc but after I shut down I touched the bottom back of my case was surprised how hot it was. It was hot… not molten hot, but you did not want to keep you hand on it for too long. The 6850’s have there own built in fans that vent all heat out the back of the case. My guess is it’s the metal brackets from the graphic cards dispersing residual heat into the case frame. Only other thing I can think of it’s a pocket of dead air under the graphic cards (between the second Graphic Card and the bottom of the case) ~but I would think the graphic card would suck it out with its fan. 1st off is it normal? 2nd something to worry about? With a single card I remember it being warm but not hot to touch. I have 2 legacy PCI slots open. The rest of my case MB Graphic card and CPU temps are in operating tempter range (normal) 38-40c range and no more than 60c on the graphic card. (it is not in the red not even close ~ via ATI Catalyst sensors)

What do you think?

Modern cards run hot, and the temp ranges you quote are about right.

The one thing you did not specify is the type of case and the type/number/placement of fans.

Without knowing it is hard to say, but your system may benefit from an additional fan or two to improve overall throughput of fresh air.

I would not be concerned about touching the metal, the hot air over time will of course tend to heat up metal rather nicely

I imagine you have monitored temps on the cards themselves and they are well within normal operating parameters.

38-40C is nothing for a modern day card, my old 8800GTX's i used to run in SLI ran at about 90C EACH under full load.

Remember that head rises so the head coming off the top of the lower card is being sucked straight into the top card, you need good air flow from the front of the case, or at the very least for an SLI/CrossFire setup a side fan, that can blow directly onto the cards,

I highly doubt the system shut down due to the cards heating up, but to check, you need to get software that can monitor them while your gaming, and can record it.

How strong is the Power Supply that you run?

http://www.newegg.com/Product/Produc...82E16811156063

Raidmax Smilodon not an elite case by any means but real easy to build with.

Power supply is a 700 watt ozc this is not hot and is mounted on the top

http://www.newegg.com/Product/Produc...82E16817341018


Just added a gelid fan to the back of the case120mm
http://www.newegg.com/Product/Produc...82E16835426014

The front fan is original (raidmax 120MM) and the so is the graphic card fan and CPU case fan. 80MM raidmax's

I have a program that show temps of things, but none that you can look at while playing without reducing a screen. (Well I may have to take that back PC probe is one that might I will have to test it) But for sure I do not have one that records reading. I don’t think PC probe looks at graphic cards.

Make sure the lower fan is actually working. You may want to check to see how much air it actually moves (cfm). Overall, the temps you quote are nothing to worry very much about.

As long as the operating temperatures of the cards are ok, I wouldn't worry about it too much. Although it may indicate a dead air pocket or less than great airflow, the case is acting as a heatsink to dissipate the energy.

Of course, running two video cards will make more heat, and the two fans will be competing to exhaust the incoming air. Many newer cases, especially ones designed for enthusiast systems, will have vent holes and/or fans mounted on the side of the case over the PCIe slots to supply more air.
Your case might benefit from a front mounted fan (blowing in) or you could cut some vent holes on the bottom, below the video cards, to allow more air intake.

He is talking about ambient temp in the case here, not temps of gpu/pcb etc.

In any case 60c for a card is nothing at all, my GTX480 will hit 100c without any fuss at all, and this is well within normal limits.