Hi.. I have a PC which has a core2 quad q9400 cpu, 500watt psu, 4gb ddr3 kingston hyperX ram and G41M-P25 msi motherboard.. I already own 2 graphics cards.. The nvidia 9800GT 1gb ddr3 (600cc 900mc DX10 support) and an ati radeon 5570 1gb ddr3 (650cc 900mc DX11 support).. The fisrt one is a bit higher in benches, but the second one supports DX11.. So my problem is which one is better to use in my system???