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IA64 vs. Other 64-bit CPUs?
moZer asks: "There are countless reviews and comparisons between
Intel's P4 and AMD's Athlon, but so far I haven't seen any benchmarks
of IA64 versus other 64-bit CPUs. Is there anyone out there who has
experience from working with the IA64 that can say something about
its strengths and weaknesses?"
Judging by the total lack of commentary, even from this crowd, that's probably a resounding 'no'? :)
and the bits that are out (test/development) are running at 500MHz and SUCK compared to even 32 bit CPUs.
run em any faster than 500Mhz and they cook, overheat and explode. dunno how intel expects to get em out any faster than 500MHz.
11min, on a Sunday afternoon, is hardly enough time to compose or even reformat a proper screed on how Evil Intel has or is trashing the One True 64bit architecture, the Alpha.
Sun's been doing the 64 bit thing for a while (Not being a Sun expert), at least 4 years. UltraSparc 5s (at least) have a 64 bit CPU, and supposedly the new UltraSparc IIIcu's will be whopping the pants off of anything Intel has wet dreams about making ;)
and I found this:h tm l
http://www.dl.ac.uk/TCSC/disco/Benchmarks/spec.
Not very detailed, but a broad comparison of different systems...something to start ya off.
The Itanium may never be really properly released as a production processor. McKinley is the one to watch for
Mmmmmmm
UltraSPARC I was Sun first 64 CPU, back in 95 as I recall. Of course you needed to wait until Solaris 7 before you got a 64 OS and hence the ability to use a 64bit address space. USI chips are detected by most 64bit versions of Solaris and it reverts to 32bit mode (I have some pre-beta UltraSPARC I hardware). This can be overridden, but leaves you vulnerable to a user land hack, which can hang the box.
Running at 167MHz these chips were hotish for their time, but compared to USII (now at a maximum of 480MHz) or USIII (just recently 1050MHz) they are rather slow. Every three years or so Sun rework the SPARC design to have better pipelines, better prediction, more TLBs etc. and speed increases in-between odd number releases are just fabrication improvements. Sun is a chip design company not a chip fabrication company.
It's hard to compare Itanium with SPARC, PA-RISC, PowerPC and Alpha - as far as I know there are no benchmarks in which is performs very well against modern 64bit RISC chips, Integer and particulary FP performance is generally considered rather inferiour.
The true test of a server class CPU is how well it handles cache coherency and memory latency issues on machines designed to support 8 or more CPUs. Itanium has not been shown to scale to these numbers. This may of course be because it's not yet been used in a server platform which supports that number of CPUs.
What I find particularly intriging is how Intel's marketing department is going to handle the clock speed differences in their product range. They have always used MHz as a marketing tool, but now they're going to have to concede that their prestigious server CPU is almost half the clock speed than that of their desktop CPU.
# init 5
Connection closed.
Oh...
The F-CPU project has been around for a good long while, and is supposed to be 64-bit. The idea of an opensource CPU is a neat idea, I must admit. Unfortunately it hasn't been updated in a while.
I'll show you my web server - a KN15 Alpha CPU in a DECStation 3000/400 - It's from the early '90s (I don't know precisely, but pre-93 for sure)
I love that little over-engineered thing to bits.
:-)
"Intel Inside - The worlds most marketable warning label"
Yes. There is a comparison of IA64 -vs- The Rest.
You can check out the details at spec.org,
but I've found Ace's Hardware Top 20 Review to be a more concise and readable version.
You can see that IBM's POWER4 has a fp peak of 1169,
while Intel's Itaniam has a fp peak of 701. In int performance, the Itanium is pretty dismal.
Spec2000 int here and Spec2000 fp here.
highlights for int base:
790-POWER4 1.3Ghz
677-AthlonXP 1.6Ghz
648-Pentium4 2.0Ghz
621-Alpha 21264C 1.0Ghz
569-PA-RISC 8700 0.75Ghz
537-UltraSPARC III 1.05Ghz
461-PentiumIII 1.13Ghz
410-MIPS 14000 0.5Ghz
379-Itanium 0.8Ghz
99-PowerPC 604e 0.25Ghz
highlights for fp base:
1169-POWER4 1.3Ghz
960-Alpha 21264C 1.0Ghz
827-UltraSPARCIII 1.05Ghz
734-PentiumIV 2.0Ghz
701-Itanium 0.8Ghz
624-AthlonXP 1.6Ghz
581-PA-RISC 8700 0.75Ghz
463-MIPS 1400 0.5Ghz
340-PentiumIII 1.0Ghz
91-PowerPC 604e 0.25Ghz
The Itanium gets wacked pretty badly in the int scores, but does respectably well in the fp code which is far easier to extract parallelism from although it is beat by the POWER4, UltraSPARC III, and Alpha 21264. Even HP's 8700 isn't far behind.
Even in the Itanium's strongest field, floating point, its little 32bit cousin, the PentiumIV, smokes it.
The reason you don't see many reviews is because its a pretty slow chip, especially compared against the POWER4. Actually the reason you don't see reviews is because gamers who own web sites write reviews for the large readership of gamers who care about the fastest video card and CPU for their games. The market for an expensive 64bit shootout is pretty small. But its easy to afford a new video card or CPU.
Heck, Intel gives them out for free if the site words a 10% win for Intel as "wiping the floor" and a 10% win for AMD as a "narrow victory"...
To start off, there's an error in your question. There's no such thing as ``the IA-64 CPU.'' IA-64 is the instruction set architecture behind Itanium and the around-the-corner McKinley, and while I could list all the features and shortcomings behind it, it'd be a boring and technical explanation.
You can jump to conclusions, if you wish, by looking at Ace's Hardware SPECmine database, which contains all current SPEC2000 results. In case you don't know, those are the industry standard benchmarks. Here is a sample query of the SPEC2000 integer benchmarks, and here is a sample query of floating point results. As you can see, there are always better choices than the Itanium, and mostly from vendors who have been in the field of 64-bit processors for long, and probably with better prices too. You can never underestimate how important vendor reputation and experience is.
I alluded to the shortcomings of the instruction set of Intel's 64-bit offerings. Indeed, the poor performance can mostly be attributed to it (although the Itanium's poor design has helped a lot -- let's see whether McKinley fares better.) The truth is, Intel took VLIW and redressed it as EPIC; but VLIW has never been a panacea. Serial designs with out of order execution have been around longer, and worked great. The Itanium is a strict in-order processor, and the SPECint results show. And compiler technology isn't there yet; but Intel has acquired Alpha from Compaq and employed their compiler and MPU design team, widely reputed as the best in the field. Whether clever design will be able to mend the instruction set flaws, only time will tell. Indeed, the best strategy now is to wait a few years; seeing as how hardly a thousand Itanium system were actually purchased and paid for, most people seem to be taking this route. With McKinley the situation will be better for Intel, but not until the 3rd or 4th generation will the mass purchases begin, if ever.
Another common misconception is about the performance of Sun hardware. Just look at the values linked above from the SPEC benchmarks. Sun is known for scalable, reliable hardware, stuff you can depend on. But they're not the best performers by any account. The best designs come, undoubtedly, from the Alpha team; the upcoming EV8 would be the most advanced processor for a long time to come, if it weren't for Intel (who cancelled the EV8 project, obviously.) Unfortunately, Alpha is no longer a good buy, though not by technical merits. Having a vendor who will vanish sometime in the future is never a good strategy. Luckily, IBM's POWER series and HP-PA still remain, although the Precision Architecture will be discontinued some time in the future as well. IBM's Power4 design is the current king of the hill in SPEC scores, beating the closest competitors by a fair amount.
Finally, a great source of information is the Real World Tech forum, and the ``Silicon Insider'' columns by Paul DeMone, on the same website. (Paul also regularly reads the forum, and posts quite frequently too.)
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intel went and designed the ISA when people where haveing problems with this and it shows now the problems is well understood
for the real dirt on intel's IA-64 read IBM's Power4 designers comment's on Mcroprocessor Report
so right that Intel wanted an appologie (-;
really its amazing that it has had so LITTLE critics as we all know you have to make trade offs and since this promises the world it would be intresting to actually see the silicon
regards
john jones
As others have already pointed out, Itanium does fairly badly on SpecINT and moderatly well (though not spectacularly) on SpecFP, but there are other benchmarks to consider: Stream and TPC are the two that leap to mind, but I am sure that there are some others that measure more than just raw CPU performance. (you won't be running any of your code on a bare CPU anyway, so you should consider some measures of full system performance) I don't see any numbers for Itanium on the Stream or TPC web sites, but maybe I missed something.