The Hypertransport for your X2 6000 is stock 1000/2000mhz. Raising your Hypertransport doesnt increase your performance because its not using anywhere near the entire bandwidth of the Bus and most boards wont take to much over 1050/1075 without going unstable. Its tied to your boards bus speeed of 200mhz X5 = 1000Mhz. So if your overclocking and raising the Bus after a certain point you need to bump the Hypertransport multiplyer back to X4 or even X3.