Sandy Bridge, Ivy Bridge and Haswell comparison
The following table shows some Sandy Bridge, Ivy Bridge and Haswell based processors along their respective features.
- N = not enabled on the specif CPU model;
- n/a = not supported by the underlying CPU architecture
- Y = supported and enabled.
|i7-3970X||i7-2600K||i5-2400||Pentium B940||Pentium B820||i7-3770K||i5-3470||i7-4770K||i5-4570||i5-4430|
|Microarchitecture||Sandy Bridge||Sandy Bridge||Sandy Bridge||Sandy Bridge||Sandy Bridge||Ivy Bridge||Ivy Bridge||Haswell||Haswell||Haswell|
As shown above, the SKU-specific features are a terrible mess. For example, the greatest extreme processor does not support the TXT extension. The high-end 2600K does not support TXT nor VT-d. However, a humble i5-2400 does support both! The segmentation is even worse on Sandy-bridge Pentium processors: the B940 does not support VT-x at all, but the slower B820 support not only VT-d, but also VT-d w/EPT!
Ivy-bridge and Haswell are not different: the i5-3470 is more capable than a higher-priced i7-3770K, and the same is true for the i7-4770K vs the i5-4570. However, use a i5-4430 and you have to give up TSX-NI.
Why to segment the market so heavily? Disabling TSX-NI on high-end desktop class processors but not on mainstream parts will not help Xeon sales in any manner. Similarly, disabling VT-x on some of the very common Pentium-class CPU can potentially create some problems for the users, but it will of no help for Intel.
These idiosyncrasies on enabled features let me think that Intel has simply gone too far ahead in the game of capabilities capping. While is a good thing to protect sales of your server-class processors, disabling ECC will be generally enough to prevent desktop-class processor leaking into real server rooms.
Oh, one more thing: the industry is bored by ISA wars. SSSE3, SSE4.1, SSE4.2, SSE4A, XOP, AVX, FMA3, FMA4, AVX2... stop here. AMD, Intel: please, please, please design a future-looking, forward-compatible instruction set and enable it, with different performance target, on yours entire CPU line. Please, stop adding instruction every year. Beside specific situations, the software industry is anchored to SSE2/3 precisely because the market for other ISA is too much fragmented.