Lastly, with the usual Apache web-server benchmark, the Core i5 2500K performance was in front of the Core i7 970 by 36%.
There is no doubt about it: Intel's Sandy Bridge is fast. In fact, it is damn fast. The Core i5 2500K retails for just over $220 USD (Amazon.com and NewEgg.com), which is really quite a deal. As shown by many of the benchmarks, the Core i5 2500K commonly outperforms the Core i7 970 in all tests aside from those benchmarks heavily favor multi-threading with the six physical cores offered by the i7-970 plus Hyper Threading. The Core i7 970, however, retails for $900 USD. There is also the Core i5 2500 non-K processor that retails for about $10 less than the K version, with the sole difference being the 2500K being an unlocked processor so it will be able to overclock better. If doing any overclocking, you are best off with the K variant. The K variant does, however, lack VT-d support.
At approximately $100 more than the i5-2500K there is the Intel Core i7-2600K processor that is clocked at 3.4GHz with a Turbo Boost Frequency of 3.8GHz (versus 3.3GHz / 3.7GHz with the i5-2500K), has 8MB of L3 cache versus 6MB with the i5-2500K, and it also offers Hyper Threading. Unfortunately, however, we do not have access to an Intel Core i7 2600K to know how exactly that performs on Linux, but Windows publications have referred to the Intel Core i7 2600K as being the fastest quad-core CPU today.
Overall the Intel Sandy Bridge / Core i5 2500K performance on Linux is splendid and we are certainly confident in this quad-core processor that is delivered at a rather nice value. These new Intel CPUs should have no problems running great with Linux in conjunction with the new H67 / P67 motherboards assuming you are using a modern Linux distribution (i.e. Ubuntu 10.10). The only problem continuing to challenge us is the Intel HD Graphics support with Sandy Bridge, which is something we are continuing to tackle and by the time Ubuntu 11.04 rolls around it will hopefully be a pleasant "out of the box" experience for those running this new hardware.