Performance Difference: Raid 5 Vs Raid 10

With HDD being so cheap these days, for a boot/system drive RAID10 would be much more ideal.

RAID5 is used when minimal capacity sacrifice is needed for redundancy due to cost e.g. a large 8 drive storage/archive array. RAID5 also comes with severe write performance penalty if no write-back cache is used or when used needs either a BBU (from controller card) or a UPS in the case of power failure. Not the most ideal form redundancy for average desktop usage.

I second wruzy with his preference for raid 10 if performance is main concern, especially random writes. But by the time you have purchased 4 drives you have spent about $300 or so depending on what size drives you bought. The same money gets you an SSD which will get your load times noticeably faster than a disk RAID. After your game is loaded the drive performance will be not noticed. If you need space for media pick up a few large and cheap 5400 rpm drives and mirror them. Its just another way to think about solving your problem.

Ok thanks both of you for the info and advice.  
Concerning the SSDs, that's an interesting idea...

I had a question about that though. I understand the concept of what TRIM is and does, for SSDs, but in practical terms do I have to do anything to activate or use it, or is it completely automatic?

I have Windows 7, and the P7P55D by Asus, if it matters.

I'd probably be looking at this SSD:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Save yourself some money on the SSD.
http://www.bhphotovideo.com/c/product/651826-REG/Intel_...