you don't need the SSD in raid 0 they perform enough , aside you will not be able to use the trim function or the Intel tool box in raid 0 , if degradation is not important ( I means the life expectency ) you can use the SSD for the photoshop swap files , it will be very fast, but your SSD will live less longer, personnaly I don't care , try to buy better memory than OCZ, they don't have a good quote.
if you want a quiet 5870 buy a regular one and use a cooler like the thermalright look I put some pics here
I7-860 Motherboard-CPU-RAM
for your photoshop pc, try to put an ATI card also ..when you use a Nvidia for long time it's more hard on the eyes
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