can't say for sure how fast mine will go, haven't tested them enough, and my Winchester CPU sux, I think when my opteron 165 comes in December I'll be able to tell how much these sticks are good for, right now I'm just idling at 220mhz mem 2.2ghz cpu, was running at 245mhz and 2.45ghz with my patriot tccd's. Things have been a little hairy at higher clocks, oddly I can run them higher (230-240mhz) using the 9x multiplier and 166 divider on my cpu, seems the memory controller might be the limiting factor right now. So for me at least, these aren't as friendly with my cpu as my TCCD's were, but for this price they are a steal.