While Quadrant scores do not directly reflect the real-world changes to the experience a user gets, some users in the development threads were seeing gains of over 20% without much hassle. For me, my Quadrant score dropped significantly on Viper4G ROM right out of the box (evidently something to do with the Viper OC daemon or my phone not liking to be set to 2.1ghz, which is an issue with how the ROM talks to the kernel).
While my scores dropped, the additional free running memory that was provided (over 100MB additional) seemed to more than make up for the drop in Quadrant scores. Your experiences will probably vary as every phone, ROM, and kernel seem to play differently together.
If you’re S-OFF or running the 1.13 firmware, you can simply flash the kernel from recovery. If you’re 1.22+ and S-ON, you’ll need to flash via Fastboot (or potentially using the HTC Dumlock method) in order to get it to stick.
[xda-developers]