AltiVec Fractal Carbon
- Results
- Comments

AltiVec Fractal Carbon

AltiVec Fractal Carbon is a numerically-intensive parallel graphics application that uses the Velocity Engine, a.k.a. AltiVec for its computations. Version 1.3 was used in this experiment.

Results

Each row in the following table shows the average MegaFlops (out of 3 runs) obtained on each system. A score is then assigned to each platform, with a reference score of 1.00 for a run under MacOS 9.0.4 within SheepShaver for MacOS X. All guest systems were MacOS 9.0.4 except PearPC which run MacOS 10.2.

Host Operating System	CPU	Speed	AltiVec	MegaFlops	Score
MacOS X 10.2.8	G4	400	Yes	1300.7	1.52
MacOS X 10.2.8 [SheepShaver]	G4	400	Yes	854.3	1.00
Linux 2.6.8.1 [SheepShaver]	Xeon	3200	Yes	1013.7	1.18
Windows XP SP1 [PearPC]	Xeon	3200	Yes	517.7	0.60
MacOS X 10.2.8	G4	400	No	298.3	0.35
MacOS X 10.2.8 [SheepShaver]	G4	400	No	199.5	0.23
Linux 2.6.8.1 [SheepShaver]	Xeon	3200	No	108.3	0.13

altivec results

Comments

SheepShaver AltiVec results were achieved on Linux/x86-64 with a snapshot from 2005/03/14.

PearPC results were obtained with a 0.4pre build with AltiVec support on Windows. That's the prasys build as of 2005/03/16.

The program displays some glitches while computing a scene. However, this only happens when AltiVec is enabled and the program is running under SheepShaver for MacOS X.

There is no specific optimization in the SheepShaver AltiVec emulation code but some SSE. Even though the current JIT is very basic and does not allocate SSE registers, performance is again on par with a run within SheepShaver on a PowerPC G4/400.

Contrary to what people usually claim on certain forums, PearPC is clearly not the fastest PowerPC G4 emulator, and definitely not the first… The AltiVec emulation is currently twice as slow as SheepShaver, even though it performs register allocation of SSE registers. This is reasonnable though.