Linux PowerPC Blender benchmark

[commodorejohn]

It has two cores, thus performing much better when rendering is split into two threads (as you can see from the results), just like the new Amiga computer chipset.

There's also the matter of memory speed; the G4s (at least in Macs) only ever had up to a 167MHz non-DDR FSB. Even the slowest G5 machines have much faster front-side buses than that, so anything memory-intensive is going to see a significant boost on the G5.

[KimmoK]

G5 FSB...

Was it 32in + 32out hypertransport kind of bus?
For example on 2Ghz G5 the FSB ran at 1Ghz (2x4GB/s).

While G4 can do 1.3GB/s(one direction at a time) and PA6T 32 GB/s (IIRC 16+16).

[commodorejohn]

According to Wikipedia:

The processor has two unidirectional 32-bit double data rate (DDR) buses (one for reads, the other for writes) to the system controller chip (northbridge)  running at one quarter of the processor core speed. The buses also  carry addresses and control signals in addition to data so only a  percentage of the peak bandwidth can be realized (6.4 GB/s at 450 MHz).  As the buses are unidirectional, each direction can realize only half  the aggregate bandwidth, or 3.2 GB/s.

So not exactly optimal (why oh why is there still address/data multiplexing in this day and age!?) but a damn sight better than the G4.