OSNews

Performance
It's almost certain that a POWER5-derived CPU is in development. It's just a question of when it appears and what its features will be. The important thing is how its performance turns out.

The POWER5 increased in performance over the previous POWER4+ because of a series of enhancements. A dual core PowerPC derivative will have several of the same enhancements even if they are not to quite the same degree.

An on-die memory controller will reduce latency and simultaneously increase bandwidth. Memory bandwidth is linked to latency as memory has to be gathered in chunks and the less you have to wait per chunk the more you can ask for. That's a simplification, but the result can be seen on the Opteron which gets closer to its theoretical bandwidth than the G5.

Given CPUs spend most of their time waiting for data any system which increases the availability of that data is going to increase performance. The on-die memory controller of the Opteron appears to be a major reason for its strong overall performance.

If an on-die memory controller is included on a 9x0 I think it's safe to assume it too will get a significant performance boost. SMT, larger caches and other core enhancements will also be beneficial and of course a second core will double the potential computing power.

The POWER5 was designed so that any optimisations made for POWER4 will also apply to it. This is a good strategy as it seems to take years to optimise compilers to a specific CPU and means all that work is preserved. This will almost certainly also be the case for the 9x0 so compiler technology will continue to improve.

Conclusion
If the 9x0 is like my speculations, it looks on paper like it could give Intel and even AMD something to worry about. However, as always, we will not know what it is really like until it arrives and applications can be tested on the system.

When this happens is anyone's guess but I think the next version of OS X could be accompanied by some interesting new hardware. I expect the chip to arrive by summer 2005.

Now if someone were to put a Cell (co)processor beside it we'd have a different ball game...

References and Further reading

1: [Prediction]
My prediction was that PowerPC would take the lead on the desktop in 2004. They have not done this save for some specific areas. However, the fastest PowerPC is not the 970FX, it's actually the POWER5 which can execute PowerPC binaries...

[2: Barefeats benchmarks]
These tests put the G5 against Opteron and Xeon systems.

[3: SPEC benchmarks]
The Athlon and Itanium 2 systems mentioned below can both be seen here.

[4: Sci benchmarks]
Itanium, Opteron and G5 bechmarks (pdf).

[5: POWER5 benchmarkss]
Aceshardware lists a number of POWER5 benchmarks in different areas.

[POWER5 Interview]
Arstechnica recently interviewed one of the POWER5's designers.

[HT]
HyperTransport consortium members.

IEEE
IEEE also ran a detailed article on the POWER5 (pdf).

POWER5 and next generation Itanium
After POWER5 Intel will come back with the Itanium Montecito this article at Real World Tech
compares the two.

© Nicholas Blachford, October 2004

About the author
Nicholas Blachford lives in Paris. He is currently helping out on the Yoper Linux disto, learning French, Python and dreaming up a GUI for advanced consumer entertainment systems, but not necessarily all at the same time.