Itanium versus x86/x64

[gast128]

Hello all,

I was browsing the internet for performance comparisons between Itanium 2's and the latest Intel processors (core 2, core i7) but couldn't find much. Ofc the comparison is based on the specific application to test against, but one would assume that a cpu (or even memory) bound applications are good comparable.

I understand that their respective architecture is radical different (EPIC versus CISC). Naturually one would expect that the Itanium with all its rich features (128 integer registers, 128 floating point register, register renaming, possiblity to process 6 instructions in 1 clock cycle) would vastly outperform any x86 architecture, although the latter one may have a higher clock frequency (and sometimes more cores, but not many software problems can be broke up into parallel tasks).

However I cannot find much information for that. In fact some people claim that the latest x64's are outperforming the Itaniums (except for floating point calculations). The number of registers alone would make me think that an Itanium has far more chance of outperform the x86, since it has a higherchance of keepingdata in its registers without accessing (slower) memory.

Or has the x86 processors evoled so much that there is little difference anymore?

[TimP]

Quoting gast128

x64's are outperforming the Itaniums (except for floating point calculations). The number of registers alone would make me think that an Itanium has far more chance of outperform the x86

http://www.spec.org/cpu2006/results/cfp2006.html

shows Itanium less than 50% of fp performance of Nehalem, and these are benchmarks which take little advantage of vectorization, which you don't seem to like. Microsoft began cutting support for Itanium 5 years ago, so you would have to limit the operating systems where you could make a comparison.

Sure, if you want to compare Itanium server chips against Core 2 laptop chips, it's more even in performance, but they don't compete in the same markets. Are you serious about there being little difference between a laptop or netbook and a server? You will see more performance gain in laptops than in Itanium servers the next few months.

Itanium hasn't been popular among those going for HPC Challenge or Top 500 rankings lately.

Are you counting only program accessible registers, or counting renamable registers only for Itanium?

[gast128]

Thx for u answer, but it is not clear to me. Are u saying that x86/x64's are faster, especially on laptops?