old ram: Corsair XMS3 3GB (3x1GB) DDR3 PC3-12800C9 1600MHz Triple Channel Kit new ram: Patriot Viper 6GB (3x2GB) DDR3 PC3-12800C8 1600MHz Triple Channel kit I tried mixing them to get 9gb of ram, but this gave me random crashes, mostly just after i'd booted up, soo thought hmm maybe it doesn't like me mixing them, soo decided to stick with the new ram. However this gave the same problems. Sometimes it would work perfectly fine, boot up fine, run smoothly. However, most the time it would freeze a few seconds after boot, mostly when i click a link in firefox. A system restore would fix this sometimes, however i'm sick of doing a system restore everytime, which only fixed the freezing 70% of the time. I increased the paging file to 9gb, however this didn't fix the problem. Today, after a month of freezing, ive decided to put the old ram back in, and its booted and works perfectly fine. Would you suggest that the 6gb patriot ram was faulty then? See thats the thing that confused about, at times that new ram would work wonderfully. I'd be running crysis and doing several other things, using about 4gb ram, everything was brilliant. However, on the flip side as you know, it would randomly freeze whilst trying to open a firefox link! any ideas? or would you suggest i get in touch with the firm i bought it from suggesting the ram is faulty? thanks.