I installed the cyanogenmod rom on my desire, using 4EXT recovery. But ever since I installed the ROM my battery just dies around 40 or 30%. No warning, no further discharge, the battery just dies. Previously my battery was fine. First thing I tried to do was charge my battery up to 100%, go into recovery mode and wipe battery stats. This did not solve the problem.
If you want cyanogenmod rom, I suggest you to try this one :
I used that rom for several month and my Desire is very fast.