After M/B change OC went down

Hello, I swapped out a M/B, p8z68-v pro with another p8z68-v pro. Board 1had OC of 5.1, but board 2 would only OC to 4.8. Everything but the board is the same. I thought the chip made all the difference. Using the i7 2600k, mult set at 50, BCLK = 103, CPU volts = 1.5, CPU PLL = 1.90000.
Now I can't get more then mult 47, BCLK at 100.
Temps are OK. Noctua 14D, 750w PS, G-skill 128000. Settings are all the same in BIOS.

keep everything the same
but raise your BCLK and lower your Multi
I havent OCd a Sandy yet
but that has helped with older systems
also check which BIOS version the second mobo is and make sure it is updated
Different BIOS on the same mobo can affect OCs
so maybe you had a different version on prior mobo

No, this is not true with SB systems. They simply cannot be overclocked by changing the BCLK as it is the master clock for pretty much every other system clock (PCI express, hard drives...). It is not recommended to increase the BCLK at all as it can cause system damage.

This is not completely true. The chip makes up a large part of the difference, but not all. Motherboards can make a difference in the overclock as some will deliver power more cleanly. Motherboards are subject to the same manufacturing variances as CPUs are and you may have just gotten one that doesn't work as well.

@ soccerdocks- thank you for correcting me. I am an old OCer who was thinking in terms of FSB and didnt realize that about the bclk
OP please ignore that piece of advice

I still would recommend that you have the latest BIOS