Thanks for the advice! Yeah, it has 6 slots as it's one of those X58 boards which were able to handle triple-channel RAM. I believe triple channel only got used with the first generation of Core processors (like mine, an i7 920) then got ditched. I already have a set like this installed so I thought I would expand it and see how it goes. I hardly play any game other than FIFA and, at times, some driving games like rFactor 2 or Grid Autosport (which, anyway, already run fine). Yeah, the machine itself is pretty old (I started picking the parts at Christmas 2009 and finally built it at the beginning of 2010) but I swapped some parts during the years. I bought a new graphics card two years ago (the R9 270X I'm currently using) and then bought off Amazon a 500 GB SSD which I already installed Windows 10 to (not using it, yet. I'm planning to do the switch soon). I hope to make it last at least another couple of years, then I'll buy a new one altogether.