But most of these reworks just make the K8 look similar to the Core. If you read Anand's analysis of the architecture you'll see that many of the features implemented make it similar to Core. The SSE execution engine should be able to nearly match or equal the Core's. Barcelona now has an indirect branch predictor much like Core. K10 will have a dedicated stack manager like Core. Barcelona will be able to re-order loads just like the Core. AMD improved on their memory prefetchers to compete with the fact that Core has more. Performance-wise AMD will really only pull ahead where their IMC and crossbar will allow them to shine. These are programs where a great deal of bandwidth is required. For desktop programs, it remains to be seen if the IMC is really that much better than Intel's northbridge design. Intel was able to show that really good prefetching can go a long way to hide some of that latency. I think it will be a wash on the desktop. It will be interesting to see if the L3 cache of the K10 will make a large difference when comparing it to the larger shared L2 cache of Core.
Performance/watt will be interesting. AMD has made some improvements here with having the northbridge on a separate power plane. Each core can also change frequency (but not voltage) which should help current draw. However, Intel will be on a 45nm process. Due to that fact alone, I would probably call this one a wash on the desktop.
Price/performance will be excellent either way. I have no doubt that Intel and AMD will have equally performing parts across their ranges and Intel will force AMD to keep their prices low. All in all, I would expect to be able to pick up equally performing quad core Penryns and K10s for 500 or less. Awesome for us.
Overall performance: AMD's improvements simply make the K10 look more like Core on the desktop. I don't see anything in its architecture that makes it look like a core-killer for the home user. The IMC and northbridge will probably add some performance on a per clock basis. I give the nod to AMD by 5-10% on average at the same clock. Overall, I see Intel simply winning overall performance on the desktop by releasing 45nm chips at a high enough clock speed to walk away with the performance crown. In the server market, the K10 can really shine. I think once you surpass a given number of sockets in a server machine, the K10 is simply the better option. We'll have to wait and see what that number is, but it's probably going to be 4 (speculation).
All in all, I don't think that Barcelona is the killer chip we've been wanting as enthusiasts. It will make AMD competitive against Intel but we'll have to wait until the next generation to hopefully see some innovative technology to retake the crown. I could be entirely wrong and have to eat some crow, but that's my hypothesis after examining the K10's architectural improvements.