What proceedure are you using to find your overclocks and have you overclocked an athlon 64 before? the proceedure can be a bit diffrent for an athlon 64 compared to an athlon xp. Even if your memory is overclocking memory, I would kick your memory down in speed to determine your cpu overclock. I helped a friend overclock that same motherboard with an athlon 64 3000 (cannot remember the core) not to long ago and he got quite a bit of an overclock without even kicking the cpu voltage up. I dont have an athlon 64 system right in front of me but if memory serves, try kicking your cpu multiplier down one step, your hyper transit multiplier down to 3x, and your memory multiplier down to minimum (probably 100). then start increasing your cpu to see how high it goes. After you find how high the cpu goes you can work on the hyper transit and memory.
I'm no expert here (I'm running athlon xp systems), but I have worked on and overclocked a hand full of athlon 64 systems and it could be if your hyper transit multiplier is set to 5x (I think that is default on this board), you are trying to push your hyperpertransit above 1000 which can often cause problems. Also, overclocking memory doesn't always overclock that well. Ocationally you get unlucky and if it is good stuff like cosair and wont overclock, exchange it. If you manage the over clock of the cpu, memory, and hyper transit individually and seperatlly, you can find where the problem is.
Fyi it is best to start your own thread rather than asking in someone elses thread. while it is kind of on the same topic, if we get to overclocking athlon 64's and athlon xp's on the same thread, it could easilly get confusing for both of you. If you like, start another thread and pm me where it is and I can try to help.
Then again, maybe it wouldn't hurt to discuss both as it is all amd overclocking as long as people are specific. I'll leave that up to everyone else.
fyi you can only edit your post for 30 minutes here. Just post another reply.