Which one should I go for, do you think? Is 2x8 / 4x4 better? When I first built my machine, it seemed that low voltage 1333mhz ram was the only option for my rig, now after doing a bit of research if you are overclocking you can get 1600mhz?
I've chosen this SSD - Samsung 840 Series 2.5" 250GB SSD + Mounting Kit - MZ-7TD250KW - Do you think that's a good call?
Any advice would be really appreciated, also advice on overclocking?
the ram will be your worst bang for buck performance increase nothing wrong with the ram you have and you seem to have allocated a fair budget to it,
what are you doing when you feel your pc is letting you down performance wise? the ssd is good and in general you will feel like you have alot faster system with boot times and load times and that
if you have never overclocked before do your research beforehand really read a few guides like this one http://www.tomshardware.co.uk/forum/263043-11-1156-core... and try google some other ones, just take it slowly starting off keeping the figures conservative and testing for stability and not overheating, when you get started and any specific questions come up about overclocking then start a new thread asking back here
new ram definitely won't help your gaming experience, it depends on what youmean by not very well, ill take it you mean fps and then I wonder what you considor poor fps? your system would benifit from overclocking but its still very capable and should be able to play games at 1920x1080 with relatively high settings but maybe not as straight forward as just putting everything max you'll have to find the sweet spot of highest settings at most acceptable fps