I'm actually still very happy with my 2,1. Especially with Tiamo's Mavericks hack.
currently its has a 6870 sapphire card in it, which I actually want to upgrade for some better game performance.
Anyone know if its actually useful to upgrade since the PCIE-1 vs modern PCIE-3?
Would hate to put some extra cash into this machine without it having any benefit.
[edit]
Seems that the 7950 seems to be a nice one, anyone can tell me the performance on a 2,1?
http://forum.netkas.org/index.php/topic,1123.msg24704.html#msg24704
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IMO, upgrading past your 6870 isn't going to help much in gaming performance. Most modern games use Single Threaded CPU performance, which is my i5/i7 CPUs are used in most new gaming builds. Your CPUs are probably bottlenecking even that card in most modern games. You probably won't see much (if any) performance increase with a 7950 over your 6870.