Hottest card in a tri-fire sandwich?

[ubersonic]

When you have something that looks like this:

Which are the hottest/coolest cards? I'm putting three cards in one rig and I am wondering which will run the hottest/coolest so I can try and put the coolest running card in the slot that will get the least air, the cards will be a pair of reference R290's and either a reference HD5870 (which basically has the same cooler as the R290 but ironically with a better shroud) or a R270X HIS IceQ blower.

 

[Sin_Chase]

I'd say middle card, purely because it's as limited for air flow as the top card but also cannot vent the backside of the PCB to case airflow either.

 

[PaulyD]

I'd say middle card, purely because it's as limited for air flow as the top card but also cannot vent the backside of the PCB to case airflow either.

Agreed.

 

[Deceptor]

Meanwhile the CPU is having a nice time being water cooled, probably glaring at the GPUs with a troll face.

 

[Kaapstad]

Top card

I have had a couple of quick runs with four 290Xs and it seems to be the top card followed by the second then third and finally the bottom card.

Having said that it needs more testing to be sure.

 

[Drangueos]

There are some factors to consider:
Position of the case: horizontal, vertical, upside down...
Voltage and Asic of each card. (I already had same model cards with different asics and different voltages)
Speed of the fans. (I already had same model cards that one card had a faster fan than the other, was at least 300rpm difference.)

 

[ubersonic]

The case is horizontal (it's a 4U rackmount) and has a pair of 95CFM fans at the front blowing air at the cards, the room is maintained at 18c and the cards are running auto fan but with the user curve set in Afterburner (at default curve). The 290's currently max out at 74c but obviously I spaced them out, so if I drop another card in between them their temps will suffer.

 

[Exsurgo]

If you have to run the cards so close, take the plastic shrouds and GPU fans off, and then position the 95 cfm fans to direct airflow into the heatsink. Use some cardboard or plastic to ensure the airflow is directed into the heatsink vents.

I and others have done this before and it works well (although it will be terribly loud).
Ideally you want San Ace fans or a make with very high static pressure and 100cfm +.

 

[Silent_Scone]

I find with Nvidia cards it's normally the middle card but that might be the difference in blower design. Heat normally rises so it also makes sense for the top card to be hotter. Under water for me the bottom card is always the little warmer but that's different.

 

[ubersonic]

Right I have done it with the HD5870 in the middle and a R290 either side (as it turns out that HIS IceQ blowers are actually triple slot coolers) and thats working fine, ironically I think the HD5870 cooler works better than the R290 one due to the shroud aesthetic changes, but all cards seem happy and temps are good so I am happy too