I disagree. These benchmarks are a small part of the full story. They're maths-heavy (which is arguably the X1000's weak point against the G4 Macs), whereas in bandwidth-heavy apps it's a completely different story.
Or in other words -- when data no longer fits in L2 cache in G4 then 1682M is winner?
Then you have to account for the fact we're only use one core in the X1000 at the moment.
Using 2nd core wouldn't improve Lame benchmarks much.
PLUS it's unoptimised.
The OS or benchmarks? I could buy that it was using conservative memory settings but according to memory benchmarks it is not case.