You have DDR3 1600 MHz but it's only running at 1001.2 MHz. Looking at your image, the DRAM Frequency is 500.6 MHz, your memory is DDR (double data rate) so you have to (double) the DRAM Frequency (data rate) to get your actual memory speed.
The next thing to look at in the image is the FSB : DRAM and it's set at 2:6. The "6" is the number were interested in. The BCLK (cpu tab lists this as the bus speed) times the 6 equals the memory speed or 2x's the DRAM Frequency.
166.9 x 6 = 1001.2
1001.2 / 2 = 500.6
To adjust this setting you have to change the DRAM Frequency setting in the bios. Right now your at 6 but I'm not sure just what options you'll be presented with. You may see 2:6, 2:8, 2:10, etc... or you may see 6, 8, 10, etc... or you may see 800, 1066, 1333, etc....
2:6, 6 or 800 are all the same setting. The stock BCLK setting of 133 times a DRAM Freq of 6 = 800 (more or less)
2:8, 8 or 1066 are all the same setting. The stock BCLK setting of 133 times a DRAM Freq of 8 = 1066 (more or less)
2:10, 10 or 1333 are all the same setting. The stock BCLK setting of 133 times a DRAM Freq of 10 = 1333
Am I confusing you yet?
Right now your at 4GHz but your memory is running super slow. As you increase the memory speed it's going to cause the system to work harder and that's going to make it crash sooner.
To get to 4 GHz with your memory at 1600 MHz I suggest changing the following setting:
Xtreme Phase Full Power Mode - Enabled
Load Line Calibration - Enabled
Turbomode Tech - Disabled
CPU Multiplier - 20
BClk - 200
DRAM Freq - 8
CPU VCore - 1.3125 volts to start with. We can lower it later, if the system is LinX stable but running to Hot.
Raise this Voltage with this ***STOP: 0x00000101
QPI/DRAM Core Voltage - Keep this at Auto.
Increase it with this ***STOP: 0x00000124, but Keep this below 1.4 volts if possible.
DRAM BUS Voltage - 1.65 volts
DRAM Timing Control - DRAM CAS# to 8, DRAM RAS# to CAS# - 8, DRAM RAS# PRE - 8, DRAM RAS# ACT - 24
PCI-e Frequency - Leave at Auto. Try adjusting this up to 101-106 if the system seems stable but a little flaky.
Speedstep - Disabled
C1E Support - Disabled
CPU TM Function - Disabled
TurboMode Tech - Disabled
C-STATE Tech - Disabled
I'm looking at the manual for your mobo and I see some of the settings listed more than once so that's why I have a couple of them listed twice.
The speed settings I selected will keep everything sync'd just right at 4 GHz and 1600 MHz. We may need to plays with the Volts some more thou.
cup speed - 20 x 200 = 4000 MHz or 4 GHz
memory speed - 200 x 8 = 1600 MHz (cpu-z memory tab will list 800)