Hi kat22,
Actually a 223MHz increase on that cpu is about all you can expect. Generally the TBird's have been getting a 100MHz to 200 MHz overclock potential.
My 1.1GHz goes to 1.313GHz nad my 900MHz will only do 1024MHz.
The problem isn't your ram.
The problem is that you can't increase the voltage on the TBird systems past the design of 1.85 volts. (I saw what you had yours, slight variences happen).
If we could change the voltage higher with proper cooling I think we could get better performance.
Be happy with your 1223!