well couldn't part of the skyrim issue be the cpu, isn't it a quad core recomending game, so trying to get high or max with a 3ghz core 2 duo could be his issue, which of course that would lead us to this same recommendation as core 2 quads are rediculously overpriced, the only one on newegg, the q9550, is still 300, and the i5 2500k kills it and is 220. but since you're doing this you might be able to just keep the 2 250's for a while and save up for a single 580 or something which should max out everything for a while, and later on you can grab another instead of having to replace 2 560 ti's which would only last a little bit longer, and also sli can cause issues in some games, so a single is always better really.