Intel's Core i3 2000 lack of O/C will not help AMD's sales in the low end market, it is the half EU's and the low performance of integrated graphics in Intel's low end chips that will help AMD's Llano cpu's to compete in that Market sector. Both SB and Llano will be at 32mm and both Quad core CPU's will have the same die size at ~200-220mm. Llano will be better in graphics and SB better in CPU performance, but i believe that Low End users will prefer to have better graphics and be able for the first time to get decent performance in current games from a low budget CPU/GPU.
The Core i3 2100 should be fairly close in most accounts for the CPU side compared to Llano. Nehalem had more changes in the CPU core but also gained the integrated memory controller - the combined performance gains in single thread was only 7-10%. So the performance gains from Deneb to Llano might lie 3-5%. That's not the focus I think with Llano's CPU core changes, its about lowering CPU power consumption and minimizing bandwidth usage. i3 2100, being a dual core chip has a 149mm2 die. Most will probably care about the graphics.
Situation with Bulldozer might not be too much different from Llano either when looking from a performance perspective, unless its heavily threaded. Going from 3 execution units to 2 might only reduce performance by 2-3%, or so, but its there. The higher latency data cache will impact it by another 2-3%, and the reduced size maybe additional 1-2%. L2 cache is 2MB, shared between the cores in a module, but the latency is 18-20 cycles.
They have architectural improvements, but probably there to mitigate the effects listed above. High latencies and smaller cache sizes indicate high(er) frequency design. There's a good chance that 8 core(4 module) Bulldozer parts being competitive in heavy multi-threading against competing Intel parts, but the
biggest focus about Bulldozer is probably about reducing core sizes. Servers make multi cores more useful, and being able to cram more cores without increasing die size is a very good thing against a manufacturing king like Intel.