After a couple of months of using the PC I built, decided to OC my i7 3820. long story short, I did get a stable OC at 4.5 Mhz by keeping the multiplier at stock 36 and bumping up the BCLK to 1.25. It Passed an eight hour stress test, and I've been using it for about two months now. Problem came when I decided to see if I could make it faster earlier this week.
- I bumped the multiplier to 37 and it shut off my internet while BCLK was at 1.25.
- I got curious, turned down the BCLK by a little bit, and set the multiplier to 36 again. And still no internet.
- I tried a few other combinations of multipliers and BCLKs, none worked.
I know BCLK OCs anything on the PCI-E, but it doesn't explain why it works at 1.25 and 1.00 BCLK, but not on anything between. And why does increasing the cpu multiplier knock off the internet when the BCLK is at 1.25? The computer boots up fine and works well, it's just internet that takes a hit. My internet is connected by an ethernet cable, no wireless. Also, the computer does still work reverting to stock bios settings and then re OCing BCLK to 1.25 thanks in advance!
I know BCLK OCs anything on the PCI-E, but it doesn't explain why it works at 1.25 and 1.00 BCLK, but not on anything between
It does because Intel's 1.25x and 1.00x keep the FSB/BCLK at 100MHz (the former is just "geared" upwards by 1.25x). Setting it to anything else in between takes the PCI-E bus (on which the network chip is connected) out of normal range, hence the instability.
Best to leave it at stable 4.5GHz. That's not a bad speed for that chip.