According to a video leaked on YouTube only a two to three percent OC via Base Clock adjustments will be possible.
Apparently this is because Intel has tied the speed of every bus to a single internal clock generator, issuing the basic 100MHz Base Clock, reports Bit-Tech..
Since this clock gen is integrated into the P67 motherboard chipset and transmits the clock signal to the CPU via the DMI bus, there no need for an external clock generator that used to allow completely separate control of all the individual hardware.
From the point of view of chip design this all good stuff, but from the perspective of an overclocker this is utter pants. Overclockers need to push the Base Clock and memory clock, but leave others, such as SATA, completely stable. Current motherboards allow multiple bus speeds because external clock generators are programmable via the BIOS.
One Taiwanese motherboard company said that since all the buses are linked, turning up the Base Clock by just 5MHz caused the USB to fail and SATA bus to corrupt.
Of course no one is losing sleep over this. Overclockers are “enthusiasts” and really there is little point pandering to that sector’s whims. But some motherboard makers are a little miffed that the move takes away some of their control.
But one thing seems clear from the video. Memory strap limits are at present removed on sample Sandy Bridge hardware. According to Intel’s slides, that is 2,133MHz.
The video details Intel’s upcoming LGA2011 Sandy Bridge-E and ‘Patsburg’ chipset that will replace the current X58 and LGA1366 platforms.
That one looks like the the upper limit DDR3 support currently exceeds 2,666MHz. Since that one is closer to previous generation basic designs, overclocking is still possible.
Intel still plans to sell K-series CPUs which come with an unlocked CPU multiplier. This will mean that the K-series CPU will be the only Intel CPUs capable of overclocking.
It seems that Intel is sending overclockers headlong into the arms of an AMD Fusion platform.