570 or 580... please explain the pros/cons

Question

Looking at putting together a budget list for the next budget year (not till July, but I needed a break from editing so I'm doing it now) and I've got a question about video cards. I've done a good bit of searching here, but haven't found a clear answer re: the 570 or the 580. Obviously the 580 is about $150 more expensive, so from a price point, it's not as nice. But if price wasn't an issue, and all other things were equal, what would be the benefit of the 580 over the 570? Adobe supposedly certifies both, which is nice.
I'm currently running an older 285, which is showing it's age as I get into RED Epic footage, with multiple layers, so it's time to go up in the world. Quadros are simply not even an option, price-wise, which is what has led me to the battle between these two.
My other specs are as follows, and upgrading CPU and Mobo aren't really viable options right now:
i7-920 @ 2.67 (not OC'd)
P6T6 WS Revolution
12 GB DDR1333 (to be upgraded to 24GB DDR1600 in July)
650W PSU (to be upgraded to 1000W PSU in July)
total of 6 internal WD Enterprise SATA drives (3x single disks, 1x 3-disk RAID-5)
total of 2 optical drives (1x DVD-RW, 1x BD-RW)
RocketRaid 231x PCIe external SATA controller, running a 4-disk RAID-5 G-Speed eS array and two single externals as eSATA only (don't know if this is best practice... to run single disks in the available slots on my RAID controller, but it worked... I'm sure I'll hear about it if it's not best practice! )
Completely separate question: I know this has absolutely nothing to do with how PrPro operates, but I'm curious and figured someone here might be able to answer the question. The "Windows Experience Index" for my system is 5.9 on an 8 point scale, and the primary hard disk is what has dropped it to 5.9... every other item is a 7.3 or higher. What would I need to do to my primary hard disk to bring it up into the range of my other components? And is there a point to doing so, or is the WEI simply a hype thing that Microsoft did for the consumer, and really has no actual impact on the system?

Answer 1

I agree, Harm. The WEI, for the most part, is only good for separating the obviously substandard from the barely tolerable. It is absolutely useless for comparing systems that are both reasonably fast (but one is obviously noticeably faster than the other).
On the other hand, if the OP absolutely must get a new card right away, he should go for the GTX 570 since the GTX 580's performance increase isn't worth the extra $150 or so over the GTX 570. But make sure that he gets a true reference GTX 570 if he must purchase an eVGA-branded card since the so-called "GTX 570 HD" cards from that same company are significantly shorter and come with less effective coolers that are very similar to the reference GTX 560 Ti heatsink (plus, the "GTX 570 HD" cards are based on PCBs that are only as long as a reference GTX 560 Ti board).