Whoa, that QPI is too high. Post your QPI/mem/uncore speeds, your bclk too.
My QPI for 7.8Ghz speed is set to 1.31V, 1.35 IS THE MAXIMUM you should use or the CPU will die quickly.
Try 1.4v Vcore for 4ghz, with memory 1.6-1.65V maximum.
After you manage to get it stable then lower the voltages a bit.
Keep in mind:
Max Vcore to use - 1.45V
Max QPI - 1.31V
Max memory - 1.65V
Also, you can try to raise the pll, but do not exceed 1.88V. Most chips need a notch up on this at least for 4ghz, and some need the full 1.88V. Just depends on the luck of how good a cpu/mobo you got out of the batch. Keep posting back.
for more help, try
www.ocforums.com, they are friendly and have alot more expertise with overclocking than me, and that is the forums I use every day.
Hope this helps, Ben.