TL;DR: Will I see a performance increase upgrading a 8600 GT to an HD 5670 on an mb that only supports PCIe x16 v1? Also, will this gfx card run on a pos 250w power supply? (there's a possibility they put something better in it to run the 8600, but it's acer so I somewhat doubt it)
So I'm trying to help a friend get his computer running SWTOR a little more smoothly. Not looking to turn it up to max or anything, just get it playable with others around on low settings, hopefully on a higher resolution (for perspective, he's currently running fairly smoothly with no one around, but in pvp or other group settings it slows down considerably). I'll be helping him with a new build somewhere between 6mo-1yr from now, so we're not looking for something perfect, just a way to bridge the gap.
The question is: His mb only supports PCIe x16 V1. I'm considering recommending he grab an HD 5670 ( http://www.newegg.com/Product/Product.aspx?Item=N82E168... ), but I'm not sure how well this will perform on pcie v1 rather than 2.1 (what I've read suggests that it should be backward compatible, but I've honestly never tried).
In addition, I THINK his psu is only a 250w (I haven't actually looked yet, I just googled the model number of his computer and found this page: