Memory Bandwidth Performance
To our surprise, when paired with DDR3-1333 memory the Core i7 980X Extreme was considerably slower than quad-core Core i7 processors in terms of memory bandwidth. SiSoftware Sandra 2010 results show the six-core chip was limited to around 20GB/s, while the Core i7 920 was capable of 23GB/s and the Core i7 960 of 26.23GB/s.
Results were even more disappointing when running EVEREST Ultimate Edition, where the write performance was considerably weaker for the 980X. Even the Core i5 750 was found to be much faster in both read and write tests.
Using EVEREST Ultimate Edition we also checked L2 cache performance. As you can see, the Intel Core i7 980X performs rather well here. Clearly the additional L2 cache from the two extra cores came in handy in this test.