Ok, So I got 2 MSI Lightning 5870s and put them in when I replaced the MB that went out on me (UD7) with a P6X58D Premium. Running DNETC and MW before with GTX285s in SLI, heat was not an issue, probably because my GPU Utilization hovered around ~65%.
With the 5870s, there is so little room between them in the 16x_1 and 16x_2 slots (even kinda separating them as much as possible) that they are running HOT. Using TThrottle, have it set to 95 limit just to get it to run. If I set to 90, it hovers around 91-93 and the throttling slows down the GPUs so much it makes crunching pointless.
Does anyone know if I put the 2nd card in the 3rd PCIE slot, will I murder my performance that way too? Or, is there enough bandwidth to not really make it a big issue?
I'm running a Lian Li K62, tons and tons of airflow and a H50 for the cooler. Tried H50 as intake and exhaust. Exhaust seems to have no effect on the GPUs cooling down versus intake, but my CPU runs about 8-10c hotter. Room temperature in here is only about 20c and I have the side off just to be able to crunch.
Any help appreciated, thanks.

Posted at DNETC also in case you see this there. Only running these 2 projects for the time being.

Try to use ati overdrive to lower the memory clock. My 4890 runs 90-93 C with stock settings, but when I set my gpu to 900mhz and my memory clock to minimum its running on 80-84 C . Of course when I want to use my computer to something else, I just simply disable the ati overdrive.

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..... Does anyone know if I put the 2nd card in the 3rd PCIE slot, will I murder my performance that way too? Or, is there enough bandwidth to not really make it a big issue?
I'm running a Lian Li K62

I am running a 5970 in a Lian Li case (phenom2). Reducing the memory speed on the cards to absolute minimum is a good thing, both MW & DNETC are not memory dependent in terms of bandwidth so memory speed is not an issue. I run the 5970 on both at 300 for memory, I have seen 4xxx cards run as low as 160 for memory.

Moving the card to get separation is also a thing to do, and will have an even greater effect on the heat due to separation and improved airflow. You will not murder performance. I assume its a x8 PCIe slot, and in that case will be fine, its rare to have any effect between x16 or x8 as it refers to bandwidth, and you have to have one hell of an app to fill up a x8 bus on its own, let alone a x16 - there certainly is not one in BOINCland

The other factor is that both apps are not memory dependent in terms of bandwidth, so a x8 slot is fine, will cope with ease.

Utilisation on the ATI apps is much much higher and accounts for the additional temperature on the gpu. I am surprised that cpu temperature has increased that much ..... are you sure that something else has not changed from previous setup. Its also possible that dust bunny build up on the cpu will have increased markedly with an open side to the case.

Another thought .... the front case fan on Lian Li's is usually moveable in the vertical depending on the model. Might be feasible to change the position of the fan and drive(s) cage (swop them) if it gets the fan closer to being on the same horizontal level as the gpus (or even add a second front case fan)

Regards
Zy

With the 5870s, there is so little room between them in the 16x_1 and 16x_2 slots (even kinda separating them as much as possible) that they are running HOT.
...
Does anyone know if I put the 2nd card in the 3rd PCIE slot, will I murder my performance that way too? Or, is there enough bandwidth to not really make it a big issue?

Try moving the cards so they are spaced out and have room to breathe. Since your case otherwise has good airflow you should see your GPU temps improve. Ideally you won't need to throttle them at all once they can get enough air to cool themselves properly. There shouldn't be much of a performance hit from moving that card to the third PCIE slot, if at all. Check back and let us know how things go.

I dove in and attempted to move the 2nd card to the third slot. Unfortunately, to do so would mean losing my front panel audio connector, both USB header connections and bending my board low level inputs pretty hard to get the card in there. With the frozr II heatpipe double fan contraption, there is no way to not hit that stuff. I have an extra fan here that has good CFM and static pressure. Going to figure out a way to cut a hole in the window part of the side panel and mount that fan an an intake blowing directly on the cards.

I can really tell the difference at the moment as it is night and pretty cool in here. Bottom card with plenty of cool air to breathe is hovering in the low 60s, top card is 91-94, that is with downclocking (goes against my very being to say the words)

The board just has the third slot at the very edge of the board. Kinda blows. Waiting for the replacement UD7 board to come. I'll have to see if that will be any better spacing wise in third slot. If it is, guess the Asus board will go into other case and my daughter will be getting a early gift.

thanks for the help.

.....Bottom card with plenty of cool air to breathe is hovering in the low 60s, top card is 91-94, that is with downclocking .....

Ow... thats a big difference, almost too big. Difficult to say without being there and putting it in proper context by seeing it in the flesh as they say, but a 30-34 degree difference seems a lot, even for closely packed cards.

I am not in any way going back on my thought re separation, that should happen, whatever board you end up on. Meanwhile, try swopping the cards to see if you get the same effect, its not impossible you have a duff card on its way out (or dust bunnies deep inside the card fan mounting).

Its an outside chance, so I would not get too concerned .... but worth doing a quick swop just to make sure, whilst waiting on the other board - you will not lose anything, and may save further delay if you have a duff card

Regards
Zy

I actually swapped top for bottom and vice versa last night...my thought was maybe one of the coolers wasn't on right or seated or whatever. When I switched them I got the same temps. I think it is just that the twin frozr cooler is really good, if it can get air.

hello nmeofdst8

I'm using the UD7 with 3 4890's and things are no better believe me
the cards are all slap bang up against each other which is a huge problem
i have to crossfire them to control the temps on each indipendantly as there all differant
setting the fans between 32 and 35 for the hottest one i can keep temps around the 85 degree mark but thats with adding two huge 4 inch fans pointing at the cards indipendantly controled by a bench power supply so i can turn them up and down also
i have been told that the 5xxx series all run cooler than the 4890 which wouldnt be difficult as these generate alot of heat even when the mem clock is turned down to lowest setting

hope that helps

Ian

........ For multiple GPUs (I run two hosts with 3 58xx cards) the reference cooler that exhausts out of the back of the case wins over the V2 coolers and Vapour-X cards everytime where PCIe slots are immediately next to each other.

Unless you want the UD7 for something particular the best MoBo for 3 up is the Asus P6T in my experience. Cards that don't exhaust need slot seperation and better airflow to remove the heat that is effectively exhausted into the case.

Based on what is being discussed, I will be interested to see what happens after I install an ASUS RampageII mobo w/3 slots and 3 Sapphire 5870s in an Antec 902 case (has 8 expansion slots on back). So far with 2 5870s I have not exceeded 75C on either card and most times the bottom card is only 5C cooler than the top card..... They are currently in an Antec 300 case - lots of airflow with all the fans.

I think the key is that these cards pick up air IN the case but exhaust OUTSIDE the case - it can't hurt!

Top card that was running at 90-92...RMA after it lost a power phase, over heated and smelt like a toaster oven. The lightnings have 6 green and 6 red LEDs on the back of the card to show the phases..2nd green went out. That and the high pitched screeching sound were kinda of a dead give away. 15 secs later computer shut off and wouldnt come back on until I removed that card.

Sending me a new card. I'm going to forgoe the USB headers and front panel audio and put card in bottom slot. With space heat should not be an issue. Card is running max of 71 running DNETC and only 65 running MW or Collatz. Amazing how much cooler really.

Glad there was a 3 year warranty...truth be told, 92 should not have burnt that card i dont think.