Yes, and to achieve higher results you will probably need to force your ram to run at a lower speed and give your processor more voltage. But, give it the minimum you can and try not to go over 1.45v (which will only be required when you start to overclock around 2.6+ Ghz).
Just remember to do everything in small increments. I just overclocked for my first time ever yesterday, and I reached 3.1Ghz on my Opteron 1212 (stock speed is 2Ghz, so I overclocked 1.1Ghz!) I would use a program like Orthos to test for stability (I only run it for about 5 minutes and if it doesn't error than I go farther with my overclock.) I use CoreTemp to monitor CPU temperatures and I use CPU-Z to get basic overclock info.
By the way, Opterons are awesome, I am running at 2.9Ghz with stock voltage!