I'm planning on building a machine to power anywhere from 3 to 9 - 42" LCD TVs. I'm going with the ATI Radeon HD 5870 for the eyefinity setup.
I got two simple questions:
1. Does the processor matter? Is there something I should keep in mind knowing that I'll be powering a very high res output?
2. Depending on the amount of TVs I end up getting, I might need either 1 or 2 Radeon 5870s. Any recommendation of powersupply (Wattage) for a single and dual card active (not crossfire) setup?
1) Processor will not matter for your video requirements.
2) 600W should handle the two cards, 500W is plenty gracious for one card. I used this utility to estimate:Antec Power Supply Calculator. Note that following assumptions were made: 90% utilization, 20% factor for capacitor aging, i3-2100 CPU with no overclock, blu ray player. You can plug in more specific variables if you wish. I tend to estimate high - for example, 60% utilization is probalby adequate in your case, but I take the default of 90%, and bump to the next highest 50W multiple.
The 5870 is a massive GPU, which is suited for gaming. Are you considering these cards just for the eyefinity connections? You proalby could come up with something that is much more cost effective, cooler and consumes less power - maybe a 5670, which has all the horsepower you need for an HTPC. A pair of those would only require less than 300 watts of power to run. Just a thought.