>> Does the 2.7 GHz G5 PowerMac provide twice the per-core performance
>> of the 1.8 GHz X1000?

> no one has yet provided Blender 2.62 tests run on G5 Mac.

Then let's just take 2.48/2.49 test runs (single core):

http://amigaworld.net/modules/newbb/viewtopic.php?topic_id=35671&forum=34&start=140#665585
http://amigaworld.net/modules/newbb/viewtopic.php?topic_id=35671&forum=34&start=160#665666

1.8 GHz AmigaOne X1000: 420s
2.3 GHz G5 PowerMac: 223s

For the 2.7 GHz G5 PowerMac to be twice as fast as the X1000 it would have to reach 210s. Linearily scaled, 223s at 2.3 GHz means 190s at 2.7 GHz and 206s at 2.5 GHz. So in terms of this single-core Blender 2.48/2.49 benchmark, a 2.5+ GHz G5 PowerMac is (more than) twice as fast as the 1.8 GHz AmigaOne X1000. This in turn entails that MorphOS running on 2.5+ GHz G5 PowerMacs would fulfil Mequa's wish :-)

> Untill then. G4 and PA6T is faster than G5. ;-)

In your dreams :-)

> otherwise it's [...] as modern as average PC today.

Average PC existing in the households today maybe, but not average PC brand-new for sale today, see R700 GPU, DDR2 RAM, PCIe v1.x, SATA2, USB2.