I just picked up a cheap pair of 5870s, however the noise of the fans is enough to send me insane!

My plan is to stick an Accelero S1 on each and zip tie a 100mm "Scythe Kaze Jyu Slim" it.

I am just a little worried the the 5870 may be a little too much for an Accelero S1, particularly the VRMs, has anyone had experience with this? Thoughts?

I have used an Accelero S1 with a *single* 5850: not so power hungry, but not that far from a 5870 once a bit overclocked.

Definitely, with the S1 VRM cooling will be your main problem. I used a pair of 120x25 mm of Gentle Typhoons at around 600/700 rpms, as well as 80x25 Noiseblocker multiframe at around 800 and it worked... but, you won't be able to overclock much, and you will probably not be able to pass furmark, unless you use a PWM fan that can be powered/controlled via the graphics card connector and can spin faster in the rare events where you have not enough air flow (yes, furmark and probably nothing else).

You'll have to make sure the fans are blowing directly on top of the VRM area. And, I'm not sure about one fan being enough: but a pair of 92/120 mm fans spinning at 500 to 700 rpms will work nicely (again, furmark will probably be too much).

Now, about the Crossfire thing, that is much more complicated. I'm not sure it will work, especially because the cards will be so near that the one on top will probably starve for airflow and receive lots of hot air. *If* it works, I'm 99% sure you'll need to use PWM fans, as you will not be able to keep up with the fans at a fixed low speed when you are gaming. And, of course, you will need to provide custom fan speed curves, the ones provided by default will probably not be adequate.

Now, just FYI, and as an alternative...

I am using a pair of 5850 with Accelero Xtreme Plus in Crossfire, with three slots in between (not the typical two, that is too tight, and even more for an S1), and I can tell you it works well: it is dead quiet (I would say silent) at full load and very effective.

Admittedly, I have a case I modded for extreme quietness and good airflow, with 4 500/600 rpm 14 cm fans blowing over the crossfire cards and a 12 cm @ 600 rpm exhaust fan I managed to place in the PCI slots area. So, do not expect silent crossfire in a typical config...but you might be able to get a very quiet config

Regards

Hey mate, thanks a lot for the reply

I also have (or I should say had) a 5850 but mine had an Accelero S1 with a Nexus Real Silent @ 5v. With this configuration I would say my PC was close to silent as practicable (HDD in a Drive-A-Way, Only 4 fans, all Real Silents @ 5V)

However, I think you are right, near silent + crossfire 5870s is probably not realistic

I have let them go and am looking into a single card solution with a quiet aftermarket cooler. I am thinking a GTX580 and a Prolimatech MK-13. I prefer the MK-13 over something like a Accelero Xtreme Plus as I can use my own fans.

FYI, I recently got a used 5870 which I have now attached an Accelero S1 rev. 2 to. It definitely runs cooler than the stock fan at comparable noise levels. Perhaps 20C cooler or more. So far I've stuck a 120mm Scythe Slipstream on top of the Accelero, *sucking* air (instead of blowing) up through the fins of the heatsink. I did this because my case has a front-to-back airflow, and I'm afraid a blowing fan will obstruct the airflow around the VRM. By pulling air up through the fins instead, I get better airflow around the VRM area in return for a poorer airflow on the other side of the fan.
I'm still trying to find out how low I can run the fans (both intake- and GPU-fan) to get acceptable temperatures. Right now a second 5870 wouldn't even fit in my case, because the Accelero and Slipstream are so big together, but it's my clear impression that you would not be able to have two 5870s in a case and have them be quiet at high load. Right now, the card alone is burning off around 180W.

Unless you get into water cooling (to get the heat *out* of the case effectively). That may make it possible.

My idea for future CF of 6870 with Accelero s1 is to put the fan before the GPU's, the same way that the front fan is used with the HDD's. A fan (or two) there should be enough to force the cold air over pipes, mems and VRM's.

Something like this zip tied somewhere:



Sorry for the paint (bad) skills

Could you easily make a duct that covers both cards in the above setup?