jerpelea from XDA released a new android 2.1 OPTIMISER. Check it out at the following link with full instructions.
Xperia X10: JIT for X10 2.1 OPTIMISER
Verison 2 Link
Xperia X10: Android 2.1 OPTIMISER Version 2
Xperia X10: JIT for X10 2.1 OPTIMISER
Verison 2 Link
Xperia X10: Android 2.1 OPTIMISER Version 2