The larger cache should bring some performance difference. The myth of i7-9xx having more IPC vs. i7-8xx series really needs to die already. Perhaps it started as a justification for the large price premium that i7 930 and S1366 motherboards initially commanded over S1156 and i7 860.
Final performance rating with applications and games
Core i7 870 2.8ghz + HT = 73.5%
Core i7 930 2.8ghz + HT = 73.9%
The 0.4% difference is most likely attributable to higher memory bandwidth of the S1366 platform in certain apps. Otherwise, i7 8xx and 9xx series have identical IPC.
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There is a
short article from Nordic Hardware about a new update on SB-E. Looks like SB-E delay is related to a chipset issue; and PCIe 3.0 may take time to sort out.