I have home build mid tower with 5 120mm fans running plus the CPU 120mm fan with a 500ws ATX power supply.
I have been looking to get a better power supply since I feel this power supply is not enough.
I'm getting a 750ws. Would this affect my performance in a good way or bad? Any recommendations?
here is the link:
1) A real 500W psu is more than enough to power your system.
2) The Apevia 500W, currently selling for $20 after MIR, does not make the list of recommended PSUs. At those prices, PSUs normally can't deliver rated wattage continuously, &/or don't have necessary protection features, &/or do not produce clean power forcing your other parts to work harder and wear out faster.
3) The psu you planned on buying is likely better, but once again is not recommended for reasoons shown in the review linked earlier.
4) Replacing your Apevia psu is not necessarily a bad idea. If you want to do that, this Seasonic 520W is high quality, plenty for your rig:
5) If you do replace your psu, and if you plan to upgrade your system to 2xvideo cards in the future, you may want to buy a 650W or 750W unit instead of the 520W. But you do not need to do so because you have fans.
I would replace it just because it is Apevia. This 520watt Seasonic would even run your system with 2 x 9800GT in SLI http://www.newegg.com/Product/Product.aspx?Item=N82E168...
But if you are thinking for further upgrades then a 600-750watt, Corsair, Seasonic or Antec would be my recommendation.