More G5 Benchmarks (NASA)

Its a shame that this testing wasn't done with up to date compilers. It appears that they just ran existing binaries.

On the other hand it does reinforce some things, one of which is that the G5 isn't all that its cracked up to be but isn't a slouch either. Apparently this is with old code that was written for the G4, it would be very interesting to see how everything runs when compiled against a modern compiler targetting the G5.

Thanks
Dave

Looks like well-design tests, for their purpose. Results use only a single CPU, but they note the G5s dual performance in the text: very nearly double, which is good!

I suppose they used single CPUs for fairness in comparison to Pentiums, which don't exist in duals? Fairness, of course, meaning evaluating the chip's capabilities for their very specific needs. Not fairness in terms of benchmarks for marketing, as they make clear.

They do mention that they did no optimisations for the G5, and that better compilers might give the G5 a boost in future tests. Encouraging, since the G5 did well even so!

well they are really good for apple...
the g5 2ghz single cpu is 22% slower than the 3200 intel with fsb 800. well, but if the new compilers come, with optimisations the difference is only 2%....
a dual g5 2ghz is the fastest system aviable. because the intel machines have only one bus per processor, while the ibm chip has got one for each. that is significantly faster in dual cpu mode...
peace!

Interesting!

If I'm reading this right, a single 2GHz G5 is nearly 50% faster than a 1.25GHz G4 in MFLOPS, and 25% faster than a 2GHz P4.

Impressive!

One thing that struck me as interesting:

Jet3D vector benchmark results are presented in Figures 3 and 4. Again, note that the vector benchmark does not include P4 systems because the AltiVec instruction set is only available on G4 and G5 systems. Consistent with earlier Jet3D tests, the vector version of Jet3D runs an order of magnitude faster than the scalar version (speedups of 10X-13X are typical). In this particular test, the raw vector performance of the G5 is impressive at 2755 MFLOPS, but a look at the normalized levels reveals that the G5 is nearly identical to the G4 in terms of vector performance per clock cycle. Thus, the increased raw vector performance of the G5 is largely due to its higher clock speed.

There was a lot of speculation that the Alitvec unit was bus-limited in the G4. I'm not familiar with the test in question, but this should certainly be an interesting point, no? Is anyone more familiar with the code to know if it would have been expected to benefit from the faster bus?

-Richard

So then a 1.6 G5 would not be much faster, if at all faster, than a dual 1.256?

Originally posted by Blackcat
Interesting!

If I'm reading this right, a single 2GHz G5 is nearly 50% faster than a 1.25GHz G4 in MFLOPS, and 25% faster than a 2GHz P4.

Impressive!

Originally posted by allpar
So then a 1.6 G5 would not be much faster, if at all faster, than a dual 1.256?

Prolly not, but if a SINGLE 1.6 is the same speed as a DUAL 1.25, that's still impressive, no?

I'm no math whizz, but I think a 1.6 GHz G5 is 36% faster than a 1.25 GHz G4 in this test.

Even though the margins are quite small for the benchmarks used, we have to consider that the Pentium did not use Vector processing.

For applications such as Photoshop/Final Cut/DVD authoring/Cd ripping, etc, surely we can expect the G5 to be leagues ahead, therefore. In fact, just about everything I use my Mac for on a daily basis.

Originally posted by Blackcat
Prolly not, but if a SINGLE 1.6 is the same speed as a DUAL 1.25, that's still impressive, no?

I'm no math whizz, but I think a 1.6 GHz G5 is 36% faster than a 1.25 GHz G4 in this test.

Keep in mind that these benchmarks test floating point and vector computational performance only. The programs only use 1 Mb of ram. They don't take into account system bandwidth.

So when evaluating the 1.6 GHz G5, the vector figures may not be much better than the G4, the floating point an improvement, but the data throughput on the bus will be significantly better than the G4.

Originally posted by scan300
Keep in mind that these benchmarks test floating point and vector computational performance only. The programs only use 1 Mb of ram. They don't take into account system bandwidth.

So when evaluating the 1.6 GHz G5, the vector figures may not be much better than the G4, the floating point an improvement, but the data throughput on the bus will be significantly better than the G4.

exactly, and that is much more important than raw gflops values.