IMO, those Athlon TBs 1 Ghz (AXIA) are the best, very OCable! 🙂
I have seen quite a few ppl hitting 50% of OC on these cpus(1Ghz AXIA).
You might push a little bit and get a few more Mhz from this cpu, since you have a nice mobo for OC.
Good luck!
Raf