How much better would 2x4GB be than i stick of 8GB? I have Intel i5 3570k, ASUS P8z77 MoBo, and SSD. I bought one 8GB stick of Corsair Vengeance, but then learned 2 x 4GB would be better. I'd have to sell my 8GB as I dont have the packaging.
Also, is the speed (?) 1600 ok, or is higher much better? Thanks.
If 8GB is the 'goal' then 2x4GB is your best option, but 1x8GB can work. Higher frequency, beyond that of DDR3-1600 adds very little if any benefit and on 8GB/stick density can be a problem with higher frequencies, so DDR3-1600 is fine. Memory's 'speed' is a function of both the Frequency and CAS Timings.