When building the Apache web-server with GCC 4.4.5 and having the Phoronix Test Suite automatically set the job count to twice the number of available CPU threads, the Core i7 970 came out marginally ahead of the Core i5 2500K and it required the CPU being overclocked to 4.2GHz until its performance was similar.
The time though to build the Linux kernel is much more important since it's one of the biggest and most time consuming tasks that's built by a portion of the Linux users. The Core i7 970 remained faster with a time of about four and a half minutes to build the Linux 2.6.25 kernel. The quad-core Core i5 2500K meanwhile required nearly six minutes to build the Linux kernel when running at its stock speeds. However, a six-minute build for a quad-core CPU is still great and when overclocked its numbers are more in line with the six-core i7-970 that additionally offers Hyper Threading.
With CLOMP we are able to look at each processor's static OpenMP efficiency over the number of available cores. The Core i5 2500K numbers are right in line with the Core i5 750, which is the other Intel quad-core CPU used in this test that lacks Hyper Threading support.