Intel i7 Sandybridge - 5 beeps on startup, clock interrupt BSOD

Hi built my system a couple of months ago, super fast super happy but i have been getting occasional BSOD messages "a clock interrupt was not received on a secondary processor". I've tested my memory with memtest, no issues, the only pattern with it seems to be when I'm playing a game or doing something particularly intensive, but there's no fixed pattern with it, sometimes there's no BSOD.

However the computer has recently started up with 5 beeps 1--2--3--4--5, then boots up without issues, could this be a CPU issue? I've updated my BIOS which hasnt helped.

Kingston 8GB (2x4GB) DDR3 1333MHz i5 Memory Kit Non-ECC CL9 1.5V
Samsung SH-B123L 12x BD-ROM DVD±RW DL & RAM Lightscribe SATA Optical Drive - OEM Black
Intel Core i7 2600k 3.4GHz Socket 1155 8MB Cache Retail Boxed Processor
Asrock Z68 EXTREME4 Socket 1155 8 Channel HD Audio ATX Motherboard

So memory ok, I figure I'm looking at a motherboard or CPU, any way i can narrow down the problem?  

Cheers,

ps. hope this is posted in the right place if not, apologies