AMD Athlon 64 & Athlon 64 FX - It's Judgment Day
by Anand Lal Shimpi on September 23, 2003 1:25 PM EST- Posted in
- CPUs
Where does 64-bit help?
Although the performance that will sell the Athlon 64 today has nothing to do with this, the 64-bit part of the equation will definitely play a role in the processor's future. With no final release of the 64-bit version of Windows XP, there is no popular OS support (we will touch on Linux support as well as Win64 support shortly) and no real application support at this time, but where will the 64-bitness of the Athlon 64 help?
There are three main categories that you can split up the performance benefits into: 32-bit applications running on a 32-bit OS, 32-bit applications on a 64-bit OS and 64-bit applications on a 64-bit OS; we will be analyzing each one of these scenarios individually.
Case 1: 32-bit apps under a 32-bit OS
At the launch of the Athlon 64, the predominant operating environment will be running 32-bit applications under a 32-bit OS. All performance benefits the K8 architecture will show here are courtesy of the on-die memory controller, improved branch predictor, higher clock speed and more robust TLBs - none of the performance improvements you'll see in this case will have anything to do with the 64-bit capabilities of the processor.
Case 2: 32-bit apps under a 64-bit OS
When Windows XP 64-bit Edition is officially released (a public beta is due out at the time of publication), many users will be running their 32-bit applications under the 64-bit OS.
Outside of the performance improvements that we just outlined in Case 1, there are a couple of additional benefits the Athlon 64 may offer users. Currently under Windows, although you have a physical memory limit of 4GB, any given process can only use up to 2GB of memory; the remaining 2GB is reserved for use by the OS. With the 32-bit applications under a 64-bit OS scenario, each 32-bit application could be given a full 4GB of memory to work with, instead of being limited to the 2GB Windows process size limitation. Unfortunately this benefit isn't really "plug 'n play" as the application would have to be aware that it can use the added memory, which in the vast majority of cases would require a new patch to be made available.
The second benefit the Athlon 64 could offer in this scenario comes from the availability of additional registers. Although the 32-bit application would still only be compiled to use the regular set of 8 general purpose registers and standard set of FP and SSE2 registers, the 64-bit OS would be able to reference and use all of the registers at its disposal. The performance benefits that you would see here exist in any sort of task handling that the OS would be doing (switching between applications) as well as just regular Windows performance. Granted that the performance improvements seen here should be negligible, considering the extra overhead that does exist when running 32-bit applications in a 64-bit environment (more on this in a bit).
Case 3: 64-bit applications under a 64-bit OS
The final scenario is the one that shows the most promise, yet has the least amount of application support today - running a 64-bit app under a 64-bit OS. Here, the benefits are numerous; not only do you get the performance improvements courtesy of the Athlon 64's architecture, but each application now has full access to the increased number of registers and each application can use much more than 4GB of memory.
Although the Athlon 64 can support 64-bit memory addressability, for demand reasons it only supports 40-bit of physically addressable memory - or ~137GB, not exactly a limiting factor at this point.
The performance improvements developers are expecting to see under this final scenario has been estimated to be in the 10 - 20% range in tasks that are not memory bound, meaning those areas where the application is using less than 2 - 4GB of memory in the first place will still see sizable performance gains courtesy of the availability of more registers. We will investigate a few of these scenarios to substantiate (or refute) these claims later on in the article.
Performance improvements where you are memory bound will be even more impressive; just think about how slow swapping to disk is and how much faster keeping everything in memory makes your computer.
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Anonymous User - Wednesday, September 24, 2003 - link
Well I have read the Anand, Toms, and Tech Report reviews (about to read a few more)..Anand - I do have to agree that P4ee tests shouldn't have been left out, that just doesn't look fair to the readers and does appear to show some bias. Also most of the other sites seem to have the via chipset ahead of the nvidia.
Toms review was very in depth but I have to question why he chose to include OC'd P4EE scores? I see no other reason other than to have the P4EEs at the top of every possible chart. I have always been a little leary of Toms CPU reviews. I have never read so many reviews (on one site) where AMD loses so often and by such a large margin practically every single test. I have read CPU reviews from several sites and on the other sites the XPs seem to fair quite a bit better.
And doesn't it seem like he inlcudes OC'd P4 scores in almost every single CPU review? I could be wrong here..anyone?
And in Toms own words several of the tests were intel optimized, so shouldn't the P4ee win regardless (as is usually the case with almost any appilication specific optimization)..
Tech Reports review seemed like it was pretty good. They ran several test and both the P4ee and the 64/fx faired pretty well.
I am looking foward to reading more reviews today.
I DO have to agree on one thing here though : AMD in the past has always done well due to it's pricing structure. The low end has almost always been very affordable and very competitive, and that's where they aqquired most of their user base.
To totally go against that makes sense in a financial way for AMD, but not for the customer.
With the looming prescot on the horizon I am curious to see how things turn out.
When tax time rolls around I will be upgrading my CPU and Motherboard (and ram "if" necessary), and I hope it isn't a one sided decision as far as who I go with..(heck, I just purchased an Nforce 2 motherboard (Soltek SL-75FRN2-RL) and retail Barton 2500+ for $184 shipped from newegg (will be here thursday), with hope of hitting 3200+ speeds (several seem to have had luck with it)..so it isn't like I am an intel zealot or anything).
I just hope the 64 line scales well and can keep up with the prescot. If the prescot performs as well as the P4ee things will be difficult for AMD. I hope they do well as I am interested in the 64 and if it a good choice at tax time it will get my money.
NO ONE (well in the general public) wants to pay $700-800 for a cpu, over $300 for MORE memory and $160-200 for a new motherboard when a $700-800 P4ee cpu performs almost as well (in some tests as it did lose some to the fx51)..if you have a socket 478 motherboard with the correct chipset that is.
But even then going the P4ee route you can more than likely still use your current ddr ram (anyone looking to buy a $700-800 cpu more than likely has adequate memory) and a motherboard can be had for less than $100.
I REALLY hope AMD does well, if for nothing more than the sole purpose of having more than one choice (we DO NOT want that people). Like I said I have interests in the new AMD cpus and tax time is about 6 months away, so it gives AMD time to get things rolling.
But, if the prescot performs just as well if not better (totally up in the air and we have NO benchmarks or real specs (CPU speed, etc) of any worth and cost the same if not less, the battle will be a very hard one for AMD...and my money in't brand loyal (intel fanboys take note)..
Isn't the soon to come prescot (not the initial launch version) supposed to be a new socket type, or am I on something? :-P
I have probably forgotten something I wanted to say, but I'll post again if I do.
Peace
Kevin
legionosh@msn.com
Anonymous User - Wednesday, September 24, 2003 - link
Hi Anand,Just wanted to say that I'm a bit dissappointed in your review. Not much mention of the hardware config, using nforce3 boards with a problem, and the conclusion based on comments like '(on pricing) which is a mistake for a company that has lost so much credibility'. Um, maybe in your eyes, but lets focus on the facts next time, rather than perceived credibility. I don't feel that AMD has lost credibility on the basis of benchmarks, in fact, they seem to be far more upstanding than their competitor in this regard. In any case, the A64 is shipping and beats its competitor in most benchmarks (based on results from just about everywhere except Tom's Hardware). As well, the A64 3200+ is about 50% cheaper than Intel's comparable offering, and I expect that AMD will continue to offer less expensive and better products than Intel as pricing changes - there is a long history of this situation. Your comments seem particularly off the mark when this example is considered.
I don't purchase cpu's based on a company's credibility, I buy them based on stability, performance, and architecture (ie. how long is the platform going to be around), in that order of priority. I don't feel like Anandtech helped me make a decision with the tests run or conclusion drawn. I'm sorry to see such a worthy site as yours stumbling.
Regards,
Mark
Anonymous User - Wednesday, September 24, 2003 - link
The Intel/AMD fanbois don't have anything on the NVidia/ATi ones I can tell ya, but it's still true that all fanbois are dumbest...AMD's Athlon success has been built on having better bang for buck than Intel. If they cannot offer this advantage then it seems likely that they will suffer, regardless of what the enthusiast market does.
Regardless of who has the faster chip what counts is that AMD are competitive - it's the only thing that is going to keep Intel honest on pricing.
Anonymous User - Wednesday, September 24, 2003 - link
The reason Intel chose 2MB L3 cache for the P4 EE was stated on several other review sites as "vertex buffers for many games reside neatly in 2MB of cache. Secondarily, a full frame of video at D1 resolution requires just a little more than 1MB of cache" so I'm wondering if Intel's next generation Pentium M with the 2MB L2 cache will be the next awesome gaming chip? Oh heck - just ask Intel to make the Prescott EE version with 2 MB of L2 cache and skip the L3.Anonymous User - Wednesday, September 24, 2003 - link
If you have to pay for a new system, you might as well pay for the fastest http://www.go-l.com/miva/merchant.mv?Screen=PROD&a... This thing will probably hit a cool 4 GHz with the FSB cranked up to 250 MHz (x 16) - so the answer to the Athlon 64 3400+ and even FX 52/53 already exists.Anonymous User - Wednesday, September 24, 2003 - link
"40-bit of physically addressable memory - or ~137GB" ???????40 bits gives 1024Gb NOT "~137Gb"...
I thought that anand people can at least convert between binary and decimal systems...
Anonymous User - Wednesday, September 24, 2003 - link
#73 Pick a sentence and stick with it!Anonymous User - Wednesday, September 24, 2003 - link
Agreed "BIASED" - furthermore it's more than suspicious they "forgot" to show us some P4EE-results is certain tests. It suggests P4EE was better than the whole AMD-branch, but AMD pays them more :)Anonymous User - Wednesday, September 24, 2003 - link
The Athlon 64 3200+ ($417) is definitely the most interesting offering. With the exception of Ghost Recon and Enemy Territory, it outperforms its direct competitor, which is about 50% more expensive. Intel will lower the price next month from $637 to $417, but until then is the Athlon 64 a bargain for the enthusiast (and AMD will probably adapt prices too).The Athlon 64 FX-51 is indeed the fastest desktop processor right now as the Pentium 4 EE is not really available to the enthusiast. The large L3-cache of Pentium 4 EE gives it an advantage in applications like 3D Animation, but in games the Athlon 64 FX-51 is overall the fastest processor. However, the high price tag plus the fact that you have to buy buffered RAM makes the Athlon FX-51 less interesting from a price/performance perspective.
We can't help it but geeks as we are we also like to look at the architecture. From an architectural point of view, the Athlon 64 shines: all the rough edges of the K7 architecture have been perfected, and the Athlon 64 architecture is - despite still being based on ancient x86 - a very balanced and elegant design. The rough K7 diamond has been cut and polished and shines brightly now, especially when you look at how well this CPU scales with higher frequencies. We will show you more in our next review.
One thing that could justify the rather high system cost of an Athlon 64 FX based PC is the extra memory space and performance in Windows 64. Windows 64 is not ready yet, though. NVIDIA OpenGL Drivers, for example, do not seem to support hardware acceleration and few applications have been ported so far as the OS in a beta phase. The future of AMD64 is a bit murky: many companies want to support the Opteron and Athlon 64 as a 32 bit chip, but have "a wait and see attitude" when it comes to porting their applications to 64-bit.
There are so many 64-bit roads that Intel may take, and therefore it is very hard to predict what future AMD64 has. Intel and HP are very committed to the Itanium, and the performance and industry acceptance of the Itanium are finally taking off. So we definitely can forget the scenario where Intel will ditch IA-64 for some form of x86-64, even though it is very likely that Prescott has some 64-bit functionality hidden away.
The most likely scenario is that Intel will try to push the Itanium towards the gigantic dual processor market more quickly, at the expense of the Xeon. While Madison and McKinley were typically CPUs for scientific and large database applications (backend of 3-tier model), Deerfield is already destined to find a place in front end (application servers like webserver etc.) and blade market (HPC).
When the Itanium family finally begins to replace the Xeon in both the workstation and server market, Intel can proceed with extending x86 to 64-bit as well and try to pull the plug out of AMD64. Because at that point, the Itanium will no longer be so vulnerable to poor ISV support. Introducing a form of Intel x86-64 in the coming moths would trample the Itanium sapling just at a time when it shows promise to grow faster.
Essentially, AMD has a few years to gather enough support and marketshare. AMD will have to do better than ever before, but the first steps in right direction have been taken.
For the moment, the future of AMD64 is no concern to the average user. The Athlon 64 (non-FX) line gives you excellent 32-bit performance for a decent price, and maybe even more importantly it is a much safer CPU. Replacing or inserting an AMD CPU is no longer a risky endeavour. Computer shops and enthusiasts, in particular, will appreciate this.
Anonymous User - Wednesday, September 24, 2003 - link
Wow... to tell you guys the truth, after all the hype, all the promises, and all the amd fans uttering "AMD 64" like they praying... I expected a bigger performance difference between the P4EE and the AMD64.. Like the AMD64 was supposed to crush it... but looks like the p4ee keeps up with it just fine. hmm.. so all im saying is it doesnt live up to the hype, but its fast, and it deserves props for that.