RAM & IGPU issues MoBo/BIOS

norrisman · May 15, 2015

I recently got some new RAM for my PC so I could upgrade to 16GB from 8GB. After installing the RAM everything was fine for a few hours, then I got a BSOD whenever I booted, each BSOD message was a RAM related error (MEMORY MANAGEMENT, PFN List Corrupt). I immediately ran a test using memtest86, this gave me 5000+ errors and I cancelled the scan after 1 pass because I felt 5000+ was enough errors to start troubleshooting. I couldn't however get into my BIOS to change timings/voltage because my keyboard and mouse weren't powered until windows booted so after some googling I found that clearing my CMOS would resolve the KB/Mouse issue. After clearing the CMOS only 2 of 4 RAM slots will work at 1 time, regardless of which 2 slots, single or dual channel. My first thought here was that some of my RAM had decided to just kick the bucket but I tested all of them by inserting one at a time, I also got no errors in memtest86 doing this. I then contacted a friend and borrowed the 4 sticks that he currently had active in his system, again, MoBo only using 2 of 4 slots at a time. This wasn't the only issue that arose after the CMOS clear, my integrated graphics is no longer detected, I do have a GPU but I like to have that powering one screen, the screen with my games on, then I use the integrated graphics to power my second and third screens. After some checking, neither my MoBo or Windows detects the integrated graphics.

My main questions here are, why the heck has my MoBo decided to only use 2 slots at a time and why has my integrated graphics decided to stop working after a CMOS clear?

CPU: Intel I5 3450

GPU: AMD HD 6850

MoBo: Asrock z77 Pro 3

Boot drive: Kingston SSD v300 120GB

RAM: 4x4GB Corsair DDR3 1600Mhz (cmv8gx3m2a1600c11)