Ok, I've been around computers for a number of years. I build my own, I work on my own. This, however, is something I have never seen before now. I am currently running on a budget gaming rig. Biostar A780L3L motherboard with AMD triple core 2.9 Ghz CPU, Gigabyte GV-685OC gfx card with onboard gfx disabled as it has always been, 500 Gb SATA HD. I was using 2x2Gb Wintec AMPX 1333 Mhz dual channel kit. I bought Gskill Sniper 2x4Gb 1600Mhz ram dual channel kit and installed it today. So far, I have double checked with CPUID and my BIOS and the timings are manually set to 1600 Mhz at 9-9-9-24 timings. 1600 Mhz is max RAM speed for my motherboard and 8Gb is max RAM so I know I am good there. I ran memtest86 for 2 hours with no issues whatsoever. Nothing is overclocked. Now on to the problem...when I was using the slower Wintec RAM with half the total amount, my PC ran much much faster. My Win 7 pro welcome screen lasted a total of 5-10 secs. Now, with double the ram at faster speeds, that screen takes almost 2 full minutes to disappear and my computer is just all around running like a snail. It takes anywhere from 20-30 seconds just to open Firefox when before it was nearly instantaneous. I'm at a loss. I have checked and done everything I know to do other than reinstalling Windows, which I was hoping to avoid. I have even reinstalled the old memory wondering if something was unseated while I was installing a case fan right before installing the memory but with the old memory, everything was fine.