this question may perhaps be a bit tricky. some users, like myself, may have installed a custom rom, but that alone may not have fixed the lag. i installed b2tb, but still had a lag, and quadnrant score was the same before and after the flash. before b2tb, i was on stock firmware, and my quadrant score was in the 9s. after flashing, still in the 9s. screen lag was the same. a combination of voodoo lagfix and v6 supercharger have improved my quadrant scores to anywhere in the 11s or 12s. extremely little to no screen lag and no other noticeable performance lag at all. but simply flashing a custom rom did not fix my lag.
Strictly for my ninjas
"And my time is a piece of wax, fallin' on a termite, that's chokin' on the splinters"
Devices: Huawei U8150 Ideos A.K.A T-Mobile Comet (sold)
Samsung SGH-T839 A.K.A T-Mobile Sidekick 4G (decomissioned)
ROM: GingerClone V2
Zeki 7" Jellybean tablet (tbd753b) current device