T-series are far superior to whatever AMD has currently. T7200 is probably the optimal price-bang of the even T's, of odds, T7100 or T7300. Hard disk from 7800 (7200 or 4800 rpm?, I'll assume it's 7200) is a downgrade. Otherwise, it's an upgrade, and it'll mainly show on load times.
The SLI is faster on raw benchmarks.