Took me whole day to try all of my games and here is the result
Gain more speed if MTVU is disabled(the speed if from 5 to 40 and maybe more and some of them gain more speed only on certain screens(that doesn't mean they lose speed on other screens))
Busou Renkin NTSC-J
Crash Bandicoot The Wrath of Cortex PAL
Crimson Sea 2 NTSC
Dawn of Mana NTSC
Digital Devil Saga NTSC
Dragon Ball Z Budokai Tenkaichi 3 NTSC
Gauntlet Seven Sorrows NTSC
Legacy of Kain Defiance NTSC
Malice NTSC
Mystic Heroes
Odin Sphere NTSC
Shining Force Neo NTSC
Sly 1 Thevius Raccoonus NTSC
Tales of Legendia NTSC
Xenosaga 3 NTSC
Zone of Enders 2 PAL
Games that don't work if MTVU is enabled
Marvel Ultimate Alliance PAL
X-Men Legend 2 NTSC
And as a extra info(not related to MTVU),those games gain huge(not minor)speed boost even by setting VU cycle stealing to 1
Need for Speed Most Wanted NTSC
Van Helsing NTSC
probably some other games too but I only tried changing VU stealing on games that were running at low speed