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
Sigh, the Athlon 64 FX
With the release of the 865PE and 865G chipsets, Intel has ensured that virtually all Pentium 4 processors on the market are paired with very high-bandwidth dual-channel memory subsystems. Ignoring the performance boost Intel gains by going to dual-channel, OEMs demanded a dual-channel solution from AMD simply as a checkbox feature.
Not having the time or resources to undertake introducing a brand new dual-channel desktop processor, AMD simply took their existing dual-channel design and called it an Athlon 64 FX. The existing design was the Opteron of course, and the first incarnation of the Athlon 64 FX is almost directly borrowed from the Opteron. What do we mean by directly borrowed?
For starters, the Athlon 64 FX gets the Opteron's memory controller with a slight change - support for DDR400. Offering DDR400 support on the server side is a little trickier than on the desktop for a couple of reasons; server processors must go through more validation than their desktop counterparts and adding DDR400 to the list of validated configurations would increase testing time. Then there's the issue of bringing DDR400 support to motherboards; an issue whose complexity increases tremendously as the number of memory slots you have to support grows. Given the memory requirements of the server market (and associated memory slots), it's just easier to wait on DDR400 support.
On the desktop, DDR400 support is great and the 128-bit memory controller from the Opteron is also nice to have, however there is one issue with the Opteron's memory controller that made its way to the desktop - the memory controller only supports buffered (aka registered) DIMMs. Although AMD is launching with Kingston releasing a line of HyperX registered DDR400 DIMMs, the vast majority of the desktop users have invested in unbuffered DDR400 DIMMs and spending more on registered DIMMs isn't exactly an easy pill to swallow.
AMD's justification for no unbuffered support is that the Athlon 64 FX is for the "enthusiast" community and these "enthusiasts" will want to use lots of memory of densities that are currently only available in registered module sizes. Given that very few "enthusiasts" have registered DDR400 it seems much more likely that it was simply easier to re-badge the Opteron than modify the CPU to support unbuffered memory.
What is necessary to add unbuffered support? Unfortunately, it is a CPU packaging issue and not something that can be added on the motherboard (remember, the memory controller is on-die now). AMD plans on adding unbuffered support to the Athlon 64 FX, but that will come at a later date as they will have to redo the chip's packaging. It seems likely that AMD would introduce unbuffered support with the rumored 939-pin Athlon 64 FX due out next year since they are changing the package anyways to support a different pinout.
Although AMD says that the Athlon 64 FX is for use in single processor environments only, the current version appears to have all three Hyper Transport links - meaning that it can work in multiprocessor environments just like the Opteron. AMD has indicated that future versions of the Athlon 64 FX would only have a single Hyper Transport link, but there's no way of knowing when that will be.
With the Athlon 64 FX, AMD has abandoned their model number system in favor of a series nomenclature similar to the Opteron. For example, the first Athlon 64 FX is the series 51 CPU, running at 2.2GHz. The number 51 was chosen arbitrarily (AMD confirmed this) and indicates nothing about its performance relative to any chip other than the Athlon 64 FX. The next CPU due out next year will be the Athlon 64 FX 53, and all you are expected to know is that 53 is faster than 51.
There's no criticizing AMD for their Athlon 64 FX series numbers simply because it was our distaste with their original model numbers that brought this nomenclature about. We criticized the Athlon XP for using model numbers in the first place, we complained when AMD rated their processors to conservatively and then we lashed out at them for being too aggressive with the model numbers. Look at the facts, AMD labels the Athlon 64 FX as an "enthusiast" processor, only sends Athlon 64 FX parts out to reviewers - the fact of the matter is that AMD doesn't want to face criticism about their naming system any longer so they've removed it where possible, and kept it where they thought it was necessary. AMD will get no complaints from us about the series numbers attached to the Athlon 64 FX, it remains to be seen if the Athlon 64's model numbers will suffer the same fate as the Athlon XP's.
The FX goes back to using a ceramic package, as opposed to the organic packaging that the Athlon 64 uses. Both processors have an identical 193mm^2 die size (which is massive, these will be expensive chips to make) and are made up of 105.9 million transistors. The chips run at a 1.50V core voltage.
The 940-pin Athlon 64 FX will work in all 940-pin motherboards and the Athlon 64 FX 51 will be priced at $733 in 1,000 unit quantities.
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Anonymous User - Thursday, September 25, 2003 - link
The Athlon64 FX doesn't have a multiplier lock either, but we never saw any results from that. Also I don't think a chip overclocking well means it's designed for "higher clock speeds".Anonymous User - Thursday, September 25, 2003 - link
toms just revised their review, "Update Sept 24,2003: Unfortunately we have made a mistake in the original article: In addition to the official P4 EE 3.2GHz we had included benchmark scores of the P4 Extreme 3.4GHz and 3.6GHz. These values were planned for a future THG article and were not intended to be included here. We would like to apologize especially to those readers who misinterpreted our charts. The two bars of the P4 Extreme 3.4GHz and 3.6GHz have now been removed. However, this issue does not affect our conclusion as we have only compared the official P4 3.2GHz EE to all other test candidates in our original article. For your information: The press sample of the P4 Extreme provided by Intel does not have a multiplier lock and is already designed for higher clock speeds. "Anonymous User - Thursday, September 25, 2003 - link
#81I also question why toms have a review to overclock P4 3.2 EE to 3.6 to win every performance chart. Is it fair to AMD? I like Intel CPU but I also like fair review.
Anonymous User - Thursday, September 25, 2003 - link
AMD needs to almost give this thing away so that it can sell well thus attracting a flood of 64 big developers. I think they should even do this to the detriment of their profit margins because if this doesnt sell well then all the software wont be developed. Its kinda like the chicken and the egg here and I think AMD should take a beating now in terms of $ to get this thing out and get 64 bit in the hands of the people. If everyone has it the software will follow.Anonymous User - Thursday, September 25, 2003 - link
Logic dictates that people whom use the term "fanboy" are mentally disturbed persons whom feel the need to categorize others into a certain group to make themselves feel better. On a side note though I think the Athlon64 3200+ is winner given its current availability, price, and performance. I’m just curious as to how far AMD hopes to scale the processor for the remainder of the year as though I already know there will be a 3400+ release in short time, I am wondering if there will be a 3600+ release in anticipation of Prescott. I’m also curious as to how quickly AMD will transition it to 90nm as I’m thinking one of the main reasons AMD hasn’t really made full effort in mass producing K8 processors are the manufacturing costs at 130nm. Either way it’s nice to see such a chip out, especially at the price it is being quoted for (though it seems some people are having fits that they can’t buy A64s for $100).Anonymous User - Thursday, September 25, 2003 - link
I think Intel is faring pretty well considering that AMD has reduced latency four fold with its integrated memory controller, incresed transistor performance by %30 with SOI, and doubled cache to 1MB. I think Intel will only close the gap with the upcomng Prescott but will pull ahead with LGA 775 Prescott and Grantsdale with PCI Express. Fanboys, save your speeches. Argue with logic.Anonymous User - Wednesday, September 24, 2003 - link
When is somebody going to come up with "folding" for people. We could use all the extra time people have on their hands debating what chip is better, to access their brain power to come up with cures for world hunger, A.I.D.S and introducing fanboys to fangirls. That being said, I appreciate all your opinions in helping me decide what chip to buy. Taking in to account the proccesing power I need for work and play, I have decided to buy an Xbox and a typewriter and forgo the 64 or P4EE.Anonymous User - Wednesday, September 24, 2003 - link
THIS FANBOY CRAP HAS TO STOP HOW NERDY CAN U BE??i am glad i am not so much into computers as most of u ;)...watch if one of these companies go out of business u see the survivor amd or intel making poor performing cpu's sold for $$$$ with a "take it of leave it" attitude...QUIT THE FANBOY CRAP truth is these companies don't give a shite about you only that little friend in your pocket that holds ur moneysprockkets - Wednesday, September 24, 2003 - link
The PM people believe that since they see the current situation in that Intel pays everyone not to use AMD, and that makes them a niche market. It's not due to AMD being slower or more error prone. Let's face it, Intel is bigger and has more to deal with, but as I've said before, they also can waste millions, perhaps a billion or so on Itanium and it's going nowhere. Perhaps it will now, but it's pretty stupid to see why. Sure it doesn't suffer from x86 legacy code. But look at what it took to get there, redoing software, apps, hardware, and a huge 400mm die. The Alpha people look to turn it into something, but that's alpha that made it something, otherwise it sucks.It's pretty stupid to argue here that the P4 3.2 ghz is faster or the emergency (good one :) ) edition is, the Xenon or even Itanium architecture with the cpus sharing a FSB and memory via a hub or northbridge architecture sucks compared to the hyper transport architecture the Opteron uses, and no amount of clock speed or memory speed is going to change that.
I wonder if Intel can now use it's own Itaniums instead of Alphas to run it's chip production line.
Anonymous User - Wednesday, September 24, 2003 - link
#91, That would be an expected outcome when half the tests are media/encoding benchmarks which are optimized for HT/SSE2. Not that there is anything wrong with that, just a simple note.