Hello
Alittle background:
I've had my Core i7 920 for about a year now and for almost all of its life with me its been at 4Ghz, its even reached 4.6Ghz, When I first got the processor it managed 4Ghz with a respectable Vcore of 1.26V, since then about every 2-3 months I've had to bump up the Vcore to keep stability, recently the Vcore has been 1.317V for 4Ghz so its getting to the point were I would be considering lowering the Mhz rather than increasing the Vcore even more.
Recently:
I decided to run 3DMark11 with my CPU @ its "normal" 4Ghz and as I expected it passed fine, but I had forgotten to print screen the results, so I decided to do it again, this time however I got a BSOD during the first test.
The next day I decided to run OCCT to check the stability of the CPU's overclock, low and behold at 4Ghz and 1.317V it was unstable after about 25 minutes. I then upped the Vcore to 1.32500V and tried again, however the CPU was still unstable. I then decided that 1.32500V is as much voltage as I'm willing to put through the CPU for 24/7 use, so the next step was to lower the Mhz and test for stablility.
4Ghz @ 1.317V = Unstable - 25Minutes
4Ghz @ 1.32500V = Unstable - 5Minutes
3.8Ghz@ 1.32500V = Unstable - 5Minutes
3.6Ghz@ 1.32500V = Unstable - 7Hours
Now 7 Hours of OCCT is IMO reaching or at stablility considering my PC would never be doing anything anywhere near as strenuous as OCCT for anywhere near 7 hours. So I was happy to call it stable, Howver the next day I was getting BSOD when playing Metro 2033 and a few within 10 minutes of booting into Windows, which I can't understand why.
After all of that I'd had enough and just set my RAM to its default values and set my CPU back to stock.
Today I was ready to give it another go and tried the 3.6Ghz @ 1.32500V overclock, this always BSOD's on me, either before Windows loads or when I apply even a small amount of load on the CPU. Remember this overclock passed 7 Hours of OCCT before.
I then Tried 3.4Ghz with the same Voltage but this gave the exact same results...
I'm completely confussed, How can It of been stable enough for me to use for months @4Ghz with 1.317V but now I can't enough get into windows @3.4Ghz with 1.32500V?
Here's some of my settings for the BIOS I know without checking for 3.4Ghz - 4Ghz
Multiplier x 20
HyperThreading: Enabled
Intel Turbo Boost: Disabled
BLCK 170 (3.4Ghz) - 200 (4Ghz)
Memory Performance mode: Standard
Memory speed (Mhz): Roughly 1000Mhz (3.4Ghz) 1200Mhz (4.0Ghz)
Memory Latency Timings: 8-8-8-24 1T
Memory Voltage: Tried 1.60V-1.66V (Memory is rated at 8-8-8 1333Mhz 1.60V)
Vcore: 1.317V - 1.32500V
IOH Core: 1.200V
Load Line Calibration: Enabled
Most of the others are on AUTO
Temps at 4Ghz and 1.32500V were 57,57,57,54C
System Specs are:
Core i7 920
Gigabyte GA-EX58-UD5
OCZ 3 x 1GB 1333Mhz 8-8-8-24 1.60V
2 x HD5850's Stock
Corsair HX850
Corsair Obsidian 800D
CPU and GPU's are watercooled Via Custom loop
Samsung Spinpoint F3 500GB
Lamptron FC6 Fan Controller
5 Fans
So any ideas as to why my CPU no longer wants to play ball? Oh BTW sorry about the really long post...