Intel Quietly Adopts AMD's x86-64

HishamMuhammad writes "The rumors reported earlier at /. are confirmed. The latest offerings in the Pentium 4 family now support AMD's x86-64 architecture, even though Intel is not willing to admit it very openly, by using cryptic names like EM64T and (gasp) IA-32e. (The naming issue was discussed on lkml, and the consensus there was to use 'x86-64,' even though sometimes AMD refers to it as 'AMD64'). Intel's FAQ admits their implementation is basically compatible with x86-64, except for the minor differences that have always set Athlons and P4s apart. It's about time Intel jumped on AMD's bandwagon, since its homegrown 64-bit architecture seems not to be doing very well."

Comments

Re:Just as a side note

[Anonymous Coward]

The primary reason seems to be that the dashes and underscores in x86-64 and x86_64 would have caused havoc with much of thier package management software.

Re:Just as a side note

[euthyphro]

Solaris also elected to use "amd64":

1 $ uname -a
SunOS xxxxxxx 5.10 s10_72 i86pc i386 i86pc
2 $ isainfo
amd64 i386
3 $ isainfo -v
64-bit amd64 applications
sse2 sse fxsr amd_3dnowx amd_3dnow amd_mmx mmx cmov amd_sysc cx8 tsc
fpu
32-bit i386 applications
sse2 sse fxsr amd_3dnowx amd_3dnow amd_mmx mmx cmov amd_sysc cx8 tsc
fpu

Itanium isn't 'bad'

[vasqzr]

Sure, you can't build a $1500 Itanium box, but at the same time, the second fastest computer in the world is powered by Itanium processors. So is the fifth. AMD Opterons power #17.

Cringely called it...

[Anita Coney]

Back on December 26, 2002, Robert X. Cringely stated this would happen.

Re:silly question

[Clay Pigeon -TPF-VS-]

Yes. At least with AMD's implementation. I am not sure about Intel's. AMD64 runs x86-32 natively. IIRC there are two modes (one mode has 2 submodes). There is legacy mode, which is pure 32 bit x86 with standard registers, and then there is long mode which can either operate in legacy submode, which can run 64 bit code or 32 bit code, but is limited to 32 bit address space and registers, And then there is 64-bit mode which runs 64 bit code with all the added registers, but cannot run 32bit code.

Re:Sound fine and all... But..

[cant_get_a_good_nick]

depends. AMD has better memory architecture for once. Generally kicks ass on most loads vs. a Xeon.

Re:AMD Better Get Its Act Together

[BlueBiker]

AMD processors will soon have SSE3 and don't have much need for HyperThreading to make use of idle execution units as does Pentium 4. The highly efficient Pentium M doesn't need it either.

AMD had a 1+ year head-start distributing reference materials and winning developer mind-share. They're not likely to lose their advantage anytime soon, especially as Athlon64 is faster than current EMT64 chips in 64-bit mode, is cheaper, and runs cooler.

You can expect developers to write code that works on both architectures, it'd be unwise to release something which didn't run well on AMD's chips.

Old News

[jbischof]

Umm... we all new this back when Intel announced 64bit support and released their 64bit manual. I think that was in February.
http://developers.slashdot.org/article.pl?sid=04/0 2/24/1822229&tid=118&tid=142&tid=8

or was it when they started shipping 64 bit Prescotts?
http://slashdot.org/article.pl?sid=04/08/06/000255 &tid=118&tid=137&tid=126

Just because it shows up on the Register it is now news again.

AMD's killer advantage is HyperTransport et al

[j. andrew rogers]

The real advantage of AMD's 64-bit system architecture has less to do with its number crunching performance and more to do with the scalability and speed of its I/O and memory architecture e.g. HyperTransport. There is not much to differentiate Intel and AMD in the absolute number crunching arena, but if you start looking at scaling memory, I/O, and the number of cores that can work together, AMD64 leaps ahead.

If the big advantage of these new 64-bit processors is nominally found in servers, then AMD will clean house because their systems scale and perform VERY well in the server role compared to Intel. Sure, you may not be able to tell the difference between AMD and Intel on the desktop, but for most types of server loads, there is no contest. The Opterons are very, very good server systems, and for many types of loads e.g. database servers, they run rings around Xeon processors for a very low cost.

Unless Intel matches a very competent ccNUMA and I/O fabric to their EMT64 cores, they will not be competitive where it matters.

Re:AMD's killer advantage is HyperTransport et al

[PPGMD]

Ding ding ding... someone that actually gets it right. AMD has solved, at least in part the memory bottle neck. I have personally tested AMD Athlon 64 vs Pentium 4 HT, the Athlon 64 wipes the Pentiums nose when it comes to loading programs.

I think Intel is realizing that because they are desperate to get DDR2 and other faster memory technologies through, but it won't help until they integrate the memory controller.

I should note I was sceptical about the AMD move, but after comparing two exactly the same systems, and the AMD clobbering the Pentium 4, with the only difference being CPU and directly related components. AMD has a winner with it's Hyper Transport Bus, and it scales quite well, of course there is an upper limit because you still have north bridge to control IDE, AGP and other such. But it's a fix for our current issues, like the integrated L2 (and later on die) L2 cache during the Pentium time.

Re:And to think....

[Glock27]

Why would I want x86-64, gives my nothing but 64-bits.

Well, no...it gives you more GP registers. Applications for x86-64 Linux usually show about a 20% speedup.

Plus the extra memory addressing does have it's uses...you'll see.

Intels Itanium was a real improvement it gave you 64-bit but it also gave one so much more.

Yep...more cost, more die size, more cache, more code bloat, more compiler problems, and more headaches. By all means, enjoy! ;-)

Re:Just as a side note

[homer_ca]

No, they're model numbers. Way back when, a court ruled that you can't trademark a model number like 80486, and AMD could keep selling 80486 processors. So Intel responded by calling their 586 the Pentium which is trademarked.

Re:Just as a side note

[imroy]

Actually, AMD didn't use the complete model numbers. Their clones were called the Am386 and Am486. Just guessing, but the use of the short numbers instead of the long (386 vs 80386) probably didn't help Intels case.

Re:Intel chips miss a critical component: the IOMM

[BobaFett]

It's much worse than that, unfortunately. The bounce buffers must be allocated in the low memory (below 4G for sure), and the only way to ensure that is to allocate them at boot time. Linux kernel does it with the SWIOTLB buffer. You can specify the size at boot, but after that it's fixed. If DMA ever requests more memory than the buffer has, the kernel will panic (apparently latest 2.6 kernels have some more graceful way to handle it, but in any case DMA requests cannot be fulfilled once there is no memory for bounce buffers). On the other hand, SWIOTLB memory effectively disappears from the system.

So, if you have a nice gaming system with 256MB video card, you may need at least that much memory just for bounce buffers, or more: I'm not sure what the exact requirements are, but I've seen EM64T boxes which would be stable only if SWIOTLB is twice the size of video RAM. Half a gig of RAM not available to the system. So at least for gaming boxes, buy AMD64, don't buy EM64T.

Re:Just as a side note

[DarkEdgeX]

Actually the reason to call it x86-64 is because this is what AMD themselves called it initially.

Though I hear Microsoft has standardized on AMD64--

C:\Program Files\NTDDK\4074\bin\win64\x86\amd64>cl
Microsoft (R) C/C++ Optimizing Compiler Version 14.00.31008.15 for AMD64
Copyright (C) Microsoft Corporation. All rights reserved.

usage: cl [ option... ] filename... [ /link linkoption... ]

But you wouldn't know it from their blogs.