You know that 270 is not that difficult with a decent chip and with the proper voltages :)
I am at 270FSB right now with my setup on the IC7-G :)
When I was limited to 250FSB with the KNXP.. But I only needed a little extra voltage.. I was at 1.58v now Im at 1.650v and its stable! I am pushing for 280 or 285 (crosses fingers!)
