AMD64 Preview

Araxen writes "Over at Anandtech.com they have an interesting preview of AMD's 64 bit processor on a Nforce3 mobo. The results are very impressive with the Anthlon64 beating out Intel's P4 best processor soundly in their gaming benchmarks. This was only in 32-bit mode no less! I can't wait for 64-bit benchmarks come out!"

Comments

Opteron Benchmarks, not Athlon 64

[ultor]

The benchmarks are from a 2ghz Opteron, not an Athlon 64. It is intended to give an example of the performance from the new chip. Unfortunately, upon introduction, only the Athlon FX, running on ECC memory will be capable of using dual-channel memory. And from what I've heard, this cpu will cost in the vicinity of $600+. The first non-ECC dual-channel platform will be introduced in 2004.

64bit performance gains...

[Natalie's Hot Grits]

Before anybody starts talking about how little 64bit cpu's actually increase performance, let me tell everyone what 64 bit mode will actually bring to the table over the Opteron/Athlon64 32 bit modes:

1) more registers. This will get us fair performance increase from the start, as compilers will have more registers to work with when doing calculations on multiple pieces of data.

2) support for larger system memory sizes. This won't help you in video games, but it will help you doing high end photoshop, and other applications (provided you spend the money to get more memory put into your system)

3) native operations on 64 bit data. Typically, when someone wants to do operations on a 64 bit integer in a 32 bit CPU, you have to split up the work in software. Now with 64 bit registers, you will be able to do operations on 64 bit integers in the same time as it takes to do the same operation on a 32 bit integer.

4) when using native 64 bit mode, certain legacy instructions of x86-32 are depreciated. This is a cleanup for the x86 ISA, which in the past has contained literaly EVERYTHING that the previous generation of CPU supported. AMD's x86-64 ISA eliminates these legacy features and moves them into firmware emulation (don't worry, it won't degrade any modern 32 bit code, just terribly outdated stuff from the 386 days, which doesn't need 2GHz of power in the first place)

On top of these performance enhancements that 64 bit mode brings you, you get all of this just because you are using AMD's Opteron/Athlon64 CPU:

1) Dual channel DDR Memory interface, with memory controller on the die of the CPU. This reduces latency and improves memory bandwidth so dramatically that even Intel's off die memory controller can't keep up (this is why video games are so much faster on the amd64 platform than on athlon-32 platform)

2) HyperTransport bus to the south bridge, which will give high bandwidth access to the PCI bus, PCI-X, and other IO intensive controllers. Eventually AGP slots will be phased out for PCI-X slots which will be universal for both video, and other devices.

3) when using multiple CPU's in the same system, the new AMD-64 platform gives you dedicated memory bandwidth to each CPU installed. On the intel and athlon-32 platforms, all the CPU's in the system shared the same memory controller which runs either single or dual channel DDR anywhere from 266MHz - 400MHz.

Re:64-benchmarks wont be good

[Distinguished Hero]

How the frell did this get modded up? Please RTFA before commenting/modding.

The benchmark was against a P4 (as well as a dual Xeon), which runs IA-32 natively, not the Italium.

The A64 is a consumer chip, designed to be purchased and used by consumers. The Itanium processor costs more than a whole top of the line consumer computer. The A64 and the Italium are not targeted at the same market segment and neither is the Opteron, which is supposed to go up against the Xeon.

The reason everyone is looking forward to a benchmark of an A64 running a native 64-bit application on a 64-bit OS is that not only is X86-64 considerably cleaner than IA-32, but the A64 also has two times as many SSE2 and General Purpose registers, which should yield significantly better results than the A64 running in 32-bit mode (which is already outperforming the P4 in a lot of benchmarks).

By the way, before someone points out that the benchmarked processor is an overclocked Opteron and not an A64, AMD is currently planning on releasing a version of the A64 which is just a rebranded Opteron 1xx along with the single-channel version of the A64.

First Look at Windows XP 64bit for AMD64

[rchatterjee]

GamePC is running a first look of Windows XP 64bit edition for the AMD64 (x86-64) architecture.

Re:Not an Athlon64, but an Opteron

[MBCook]

Your comment is somewhat missleading. There are TWO Athlon 64s being launched (or as Overclockers.com called them the "Opteron that's not an opteron but is an opteron" and the "operton that's really not an opteron" or something like that). Annandtech compared the equivelent of an Athlon64 FX, not an Athlon64. Here is the skinny:

Athlon64 FX
This is a 1xx opteron. It's still dual channel, and it uses ECC memmory (for now?). This is the "performance" part, the high end one. If we're trying to find who has the fastest CPU, this is the one to test. Their tests are quite valid for this, IMHO.

Athlon64
This is the "budget" Athlon64. It only has once memory channel, I don't know if it has ECC or not. Yes, this will be slower, but it will also be cheaper and the motherboards for it could be cheaper too (since it doesn't have that second memory channel).

So, I think that this is a very important article. Look how fast an Opteron/Athlon64 FX is compared to a P4. A 2 Ghz Opteron/Athlon64 FX is beating a 3 Ghz P4. This is all on a 32 bit os and software. When you run 64 bit software that knows about all the extra registers and can do 64 bit math nativly should it need to, the computer will be fast. Tim Sweeny (spelling?) said that native versions of UT2003 (or something) was running up to 20% faster on x86-64 without optimisations; just from going to 64 bit mode. And for most of us the fact that it can manage over 4GB of mem easily for now is only iceing on the cake.

AMD has a great processor. I can't wait to see more info on these things. The fact that it does so well in 32 bit mode is important since you currently can't get Windows for the processor (there is no x86-64 version of Windows out yet). If it was a great processor, but you were forced to get terrible performance if you bought one for 6+ months (becuase it wasn't good with 32 bit software like windows and what you run), would anyone buy it? This thing is faster today, and should only get faster when you run native software. I'm saving my pennies (and yes, I know it will take a lot of pennies ;).

Re:Not an Athlon64, but an Opteron

[sirsnork]

All Opterons are made on the same line, they all have the exact same core. They are then tested to see it the work in 8way, if not they are tested for 4way and if they fail that they are tested for 2way. In 2 way they only use 2 of the 3 HT cotrollers and only one talks to another CPU (the second connects to the HT controller). In 4way config the CPU's use 2 HT controllers to talk to CPUs and one of them uses the third to talk to an HT controller (in fact sometime they have 2 CPUs talking to HT controllers, one for PCI-X and the other for all the rest). Finally in 8way 4 of the CPUs use all 3 of their HT controllers and the 4 at the edges only use 2, but again some also have to talk to the HT controller(s) on the "outside"