Opteron is just Athlon64 with a dual channel controller. Well, other things, but that for one.
I'm not condemning the final, shipping product at all. There's still a good chance they'll come out with a whiz-bang product, and I expect that to happen. But there's also a chance that it won't be quite as good as we might have hoped, sort of like the GeforceFX of the CPU world. And given the PR system, they really CAN'T come out with a bad product -- they just have to reduce the gap between actual frequency and PR number, and make sure the clock frequency is ramped up enough to have PR numbers matching Intel; obviously, if they just called it a 1.6GHz CPU and priced it lower than a 2.6GHz P4, they'd have a winner because it's going to perform WAY better than a 1.6GHz P4. What's really disappointing is that they're seemingly stretching the PR system as much as they can, in order to get PR numbers as high as possible with the lowest possible frequencies; rather than giving us a frequency which guarantees the performance will ALWAYS be at or above the PR number, they give us a stretch where maybe in some places it's not REALLY a 2800+ performance. Of course, the final product could be so significantly better that this becomes completely untrue; then again, it might not.
All I'm saying is these benchmarks are a bit disappointing given how long they've already delayed, and don't LOOK very good in terms of how much better it could get with only 5 more months. We expected to be seeing these sort of benchmarks and performance levels a YEAR ago, and they're just getting to that point now. Whatever the reasons for the delays, all it looks like to someone considering the Athlon64 as an option is they're having a much harder time reaching their goal, so MAAAAAAAAAAAYBE we'll go ahead and start looking at other products rather than continuing to be sure that Athlon64 will be what we want to use. It's just a seed of doubt for some people, where previously they may have had little to no doubt.