Following my previous post,I wanted to see how an 8 core Bulldozer might stack up against an 8 core Sandy Bridge. I looked up on the net for the average perf. figures fro Thuban and Westmere and got to behardware website.It's not the most accurate list nor the best test selection,but it's a start.
Westemere @ 3.33Ghz has a 221 "points" on their scale. X6 @ 3.2Ghz has 160.
Now for an impact of adding of cores I looked at their conclusion for Nehalem->Westemere and Deneb->Thuban effect:
During our test of the Core i7-980X, we noted a gain of 16% on the i7-975, and concluded that the Phenom II would benefit more by going up from 4 to 6 cores because of the absence of Hyperthreading. A quad-core Intel with HT already makes 8 logical cores available to applications and this meant that the potential gain would be lower.

This is verified in practice as, at equal clocks, the average gain between the Phenom II X4 955 and the Phenom II X6 1090T is 24.7% (23.9% without Turbo CORE). The performance gain on the Phenom II X4 965 is a notable 18.2%.
As can be seen, with 50% more cores and same clock Westemere is ~16% faster than Nehalem in client workloads,while Thuban gets a ~24% perf. increase.

Now,with SB we will have 33% more cores and the impact according to the quote above should be 10% (50% more cores : 16% perf. increase = 33% m. cores : x perf. increase => x=10%). Add on that the IPC jump with SB of ~15%(average) and we have : 221x1.1x1.15=279 "points" . Since Westmere and SB are built on the same 32nm node,I suspect intel won't hit 3.33Ghz for a chip with 33% cores and IPC increase while staying in the 130W bracket.So let's assume they have to cut on the clocks by 10%(a bit generous) and we have a 3Ghz 8 core Sandy Bidge with approx. 279/1.11~=251 "points" . Turbo is counted in the scores since both Westemere(a base for results) has a Turbo mode up to 3.6Ghz.But let's assume a better Turbo in SB adds another 3% on top of the score above : 251x1.03= 258 "points".

On to the Bulldozer 8 core. I've done some speculative calculations and already got some numbers for BD. To cut the story short,a 4Ghz 125/140W model with Turbo up to 4.5Ghz and 10-15% IPC jump. Following the behardware's Deneb->Thuban jump(due to sheer core /thread uptick,no IPC change) we would have : 33% more cores : x% perf. increase= 50% m. c. : 24% p. increase => x=18% . The clock difference between 4Ghz and 3.2Ghz( for Thuban in behardware's chart) is 25%.The IPC difference I would pick 12.5% (10-15% arith. mean).The scaling hit is 10%. Turbo affecting scores is 3% due to higher Turbo on BD vs Thuban,the same as for SB's better Turbo effect. All summed up : 160x1.18x1.25x1.125x0.9x1.03=246 "points" .Thuban @ 3.2Ghz has 160 "points" . This correlates well with the 4.7-5.4Ghz perf. range of X6 Thuban I speculated before(~5Ghz/3.2Ghz=1.56x~=246/160).

X8 BD @ 4Ghz with the new Turbo should be generally comparable(4% difference),performance wise, to 3Ghz 8 core Sandy Bridge with the new turbo.Die sizes will be different though and I expect that 8 core Sandy Bridge will be noticeably larger chip(300-333mm^2) while for BD X8 i expect 200-220mm^2.