I'm putting together a Sandy Bridge Quad Core i7, with 32 GB RAM, on an ASUS P8P67 board, to go in a rackmount chassis. The chassis has two front openings for 120mm fans. The only (pre-existing) exhaust openings in the chassis are in the rear, for two 80mm fans.
I intend to overclock to 4.8 GHz - a stable value - this is not for gaming, but a company computer for a multi-track recording studio. Most of the time, I'll probably never push it to the limit, but when I do, it will likely be for hours at a time.
I need this to be a quiet computer, so I'm using some fans that don't push a lot of air. After reading some of what you guys have suggested to others, I've added an exhaust fan to the top of the case (it's going in a server rack, but luckily, I don't have to cram this in with other equipment right on top of it).
Here's what I computed, based on the fans' specs...
Well, I just found something interesting on motherboardpoint.com - a formula for this calculation. I entered the formula into a spreadsheet to make it easy for anyone to use, but the input temps are in Farenheit. Maybe someone can take this and make a handy little pop-up app out of it, which might be handier than opening a full spreadsheet application every time. Anyway, it's rather simple, (you need to download it, THEN open it)...
That works, and if there seems to be a problem with the pressure, you can always do an exact reverse on the fans and vent through the front as long as there isn't anything else blowing hot air near the back of the case this is in
I see. nothing is behind that rack, so it's a possibility. But I saw somewhere else on this thread that it's a good idea to have a bit more "push" than "pull", creating a slight vacuum in the case. Not sure why... perhaps to bring air in through miscellaneous crevices?
I could create a slight pressure in the case, rather than vacuum, by increasing the bay fan to 120mm (Silverstone CPF51-B) and slightly increasing the overall air throughput in the process. The intake would want to pull in 210 CFS, probably averaging around 190.
I suspect I ought to stop whipping this dying horse, though.