
The anticipation surrounding AMD's upcoming Socket AM2 platform is amazing to witness. On the one hand, there is hardly a secret about it that had not been discovered months ahead of the product launch, so there is discussion of it all over the place. On the other hand, the enthusiast crowds are eager for the new platform, which will be associated with important changes in the PC world; these include the introduction of Microsoft's Vista operating system and AMD's first quad core processors. However, AM2 has not been about being better or faster until lately.
It is equally amazing to see everybody anticipating the change in generation, although the switch to DDR2 is not expected to make a great difference in performance by itself. As our benchmarks show, going from DDR400 to DDR2667 with current silicon would not make a noticeable difference at all, because the integrated memory controller suffers more from relaxed memory timings than it can gain from speeding up clock speed via DDR2. Whether the current engineering sample processors actually suffer from a memory controller bug is hard to say. This could also be due to information that was released intentionally to prevent people from doing early benchmarking.
In order to make the new platform more attractive, AMD cannot sit back and rely on the expected attractiveness of 1 and 2 GB DDR2 DIMM pricing. It needs higher memory speed in order to provide additional performance value, while maintaining lower speed DDR2 as an option for budget computers based on the Sempron. Although the June 6 launch will be somewhat late, it still is within the projected Q2 time frame, and would allow the launch to go hand-in-hand with a good DDR2-800 memory supply. Let's also not forget that Intel is going to introduce DDR2-800 support at around the same time as well...
Most computers today are equipped with 512 MB or 1 GB of memory. While a gigabyte still seems to be fairly enough, we predict that 2 GB will be the reasonable minimum for those who want to do more than just occasional gaming or browsing the Internet by the end of this year. This not only applies to particular applications and their increasing demands for RAM (let's not forget Microsoft Windows Vista either) but will be the consequence of changing user behavior as well. Dual and multi core processors provide enough performance to process multiple tasks simultaneously, and they help to eliminate annoying system delays even with more and more services running in the background. So why should users think of shutting down demanding applications before launching other programs?
They won't! A few weeks ago I caught myself running a multitude of programs on my desktop PC. This is something I would not have done two years ago, because system responsiveness would have been poor. Thanks to the dual core processor there is enough performance to run and switch tasks, and 2 GB or of more system memory makes sure application data does not get swapped to the hard drive.
So what does this have to do with AMD's upcoming platform?
AMD Embraces The Sweet Spot, Jumps On Intel's Timing
We have no reason to doubt AMD's statement that the switch from DDR to DDR2 technically could have been made in 2005. With DDR2 being more expensive than DDR, and unable to increase system performance by a reasonable amount, what sense would that have made? The answer clearly is "none". We do not want to speculate over the existence of a bug in current silicon as reported on the web, since the processor we used is too far away from mass-production anyway.
The adoption of DDR2 memory for Intel-powered systems turned out to be much slower than expected, and the breakthrough was not until the introduction of DDR2 support for the mobile platform. While this did not actually hurt Intel, such a slow technology adoption last year could have stopped the recent tailwind that has put AMD into its current favorable position.
The situation is different now. While there is still little performance benefit in using DDR2, memory configurations of over 1 GB are going to be cheaper soon with DDR2. It won't be long until regular 1 GB DDR2 DIMMs-non-enthusiast products-will hit the price points that are currently occupied by basic DDR400. Finally, 2 and 4 GB RAM configurations will become fairly affordable. Introducing a new platform while waiting for the memory to become reasonably priced is pretty much like the story of the chicken and the egg: which comes first? Fortunately, since both AMD and Intel are making the switch to DDR2-800 at the same time, we expect this transition to be both quick and beneficial to everyone.

In terms of processor pin count, the new socket was not really necessary to support DDR2 memory. However, AMD decided to make physical modifications in order to prevent people installing the wrong processor into their systems. So Socket AM2 (or M2, as it was called before hitting intellectual property issues) has a total of 940 pins. Despite this, it is also not pin-compatible with the Opteron's Socket 940.
Simultaneous to the AM2 platform launch, AMD will also release a full processor line that consists of six Athlon 64 X2 dual cores, two Athlon 64 single cores, and six Sempron class value processors. In addition to these, AMD will respond to Intel's announcement that it will fit all mainstream desktop processors into a 65 W power envelope: while regular Athlon 64 X2 models are specified to a maximum TDP of 89 W, every processor up to 4800+ will also be available as a low power version. All single cores and the 3800+ X2 dual core will even maintain an impressive 35 W power envelope. These will all be fabricated on 200 mm wafers, based on the current 90 nm SOI process. Although AMD is preparing to switch its manufacturing facilities to 65 nm circuitry on 300 mm wafers, it will take a few months before the firm can output processors in volume using this newer technology.
The introduction of the Socket AM2 platform will also change the current cooler specification, forcing the cost of a new thermal solution on those Socket 754/939/940 folks willing to upgrade. The change does not affect the maximum dimensions of the mounting frame, nor the cooler, but it redefines the clamping mechanism. This is no issue for the big players (system integrators and OEMs), but enthusiasts might have to throw their existing high-end cooling solution out of the window.
We were able to install a simple Socket 939 cooler, which should be possible with some products that are around. However, any cooling solution that has to be screwed directly to the motherboard definitely cannot be used any more, as there are now four rather than two mounting holes. Still we hope that high-end cooler vendors will offer modified mounting kits for their premium products.



The retention bracket on the right side is the new one.

Since the mounting mechanism is slightly different, you will require a new processor cooler for your AM2 system. However, many existing designs can easily be transformed to suit AM2.

No Changes In Chipset Support
As we already mentioned in our evaluation of ULi's M1697 chipset, there is no need for new chipsets for AM2, and it won't affect the chipset development of 3rd party manufacturers either. Basically, every core logic product that supports the current AMD64 processor family will also support the Socket AM2 generation, because the communication path between the processor and the system is HyperTransport.
For the time being, Nvidia's nForce4 will remain the dominant product in the Athlon 64 retail market, thanks to its broad feature set. ATI currently has its Radeon Xpress 200 family, but it is in the process of keeping up with Nvidia. In the OEM space, VIA still plays an important role, and ULi as well as SiS are still around as well (although ULi is part of Nvidia now).
| Product | Model | Core | Cache | TDP | Clock Speed |
|---|---|---|---|---|---|
| Athlon 64 FX | 62 | Windsor | 2x 1 MB | 125 W | 2.8 GHz |
| Athlon 64 X2 | 5000+ | Windsor | 2x 1 MB | 89 W | 2.6 GHz |
| Athlon 64 X2 | 4800+ | Windsor | 2x 1 MB | 89 W | 2.4 GHz |
| Athlon 64 X2 | 4800+ | Windsor | 2x 1 MB | 65 W | 2.4 GHz |
| Athlon 64 X2 | 4600+ | Windsor | 2x 512 kB | 89 W | 2.4 GHz |
| Athlon 64 X2 | 4600+ | Windsor | 2x 512 kB | 65 W | 2.4 GHz |
| Athlon 64 X2 | 4400+ | Windsor | 2x 1 MB | 89 W | 2.2 GHz |
| Athlon 64 X2 | 4400+ | Windsor | 2x 1 MB | 65 W | 2.2 GHz |
| Athlon 64 X2 | 4200+ | Windsor | 2x 512 kB | 89 W | 2.2 GHz |
| Athlon 64 X2 | 4200+ | Windsor | 2x 512 kB | 65 W | 2.2 GHz |
| Athlon 64 X2 | 3800+ | Windsor | 2x 512 kB | 65 W | 2.0 GHz |
| Athlon 64 | 3800+ | Orleans | 512 kB | 62 W | 2.4 GHz |
| Athlon 64 | 3800+ | Orleans | 512 kB | 35 W | 2.4 GHz |
| Athlon 64 | 3500+ | Orleans | 512 kB | 62 W | 2.2 GHz |
| Athlon 64 | 3500+ | Orleans | 512 kB | 35 W | 2.2 GHz |
The new processors will be based on the 90 nm cores Windsor (dual core), Orleans (single core) and Manila (value single core for Sempron). All feature the 64-bit extensions AMD64, the non-execute bit (NX) and the power saving feature Cool & Quiet. The Athlon 64 processors will also be equipped with AMD's interpretation of hardware assisted virtualization (Pacifica).



The processor we used for our tests was an Athlon 64 X2 4800+ for Socket AM2, which made its way to motherboard companies in mid-December 2005. It has the same technical characteristics as its Socket 939 brother: 2 x 1 MB L2 cache, and 2.4 GHz clock speed. However, while we could select DDR2-800 speed in the BIOS of the engineering test motherboard, it obviously did not set the memory faster than 667. As already mentioned, the memory is suspected to suffer from a performance bug, which may be true or simple a matter of the early product stage. The upcoming processor (revision F) will fix any of this; the dual core version is being shipped to motherboard partners starting this week, with single cores to follow in the middle of May.

The current CPU-Z versions do not read the memory information correctly.

We found the system to be surprisingly stable; in fact, it did not give us any problems. At the same time, it should be mentioned that Socket AM2 systems will be using the chipsets and drivers currently available, and these can certainly be called mature. From a platform environment point of view, this is a nice advantage for AMD.
The motherboard and BIOS were still in an early stage, because there were no settings to change the memory timings whatsoever. There were also plenty of BIOS options that we would recommend removing from end-user products. The memory speed could be switched from DDR2-400 to DDR2-667 and even DDR2-800. In addition, it is much easier to match an even 400 MHz memory clock speed to the 200 MHz base clock speed than it is with the DDR2-667 at an odd 333 MHz.

| Processors | |
|---|---|
| Socket 939 | AMD Athlon 64 X2 4800+ Manchester (2400 MHz 64+64/512 kB) |
| Socket AM2 | AMD Athlon 64 X2 4800+ Windsor (2400 MHz 64+64/512 kB)
Support for DDR2-667 ONLY ! Production processors will support faster DDR2-800 RAM. |
| Motherboards | |
| Socket 939 | Undisclosed Pre-Production Socket AM2 Motherboard
Chipset : Nvidia GeForce 6150 & nForce4 430 |
| Socket 939 | MSI K8NGM2
Rev. 1.0 Bios : 080012 Chipset : Nvidia GeForce 6150 & nForce4 430 |
| Socket 939 | Asus A8N32-SLI
Rev. 1.01 Bios : 1009 Chipset : Nvidia NForce4 SLI X16 |
| Memory | |
| DDR2-667 | Corsair CAM2X512A-5400UL (XMS5400 V1.2)
2x 512 MB DDR2-667 (333 MHz, CL3-2-2-8, 1T) Running at CL-4-4-4-12 Timings - not changeable in test motherboard BIOS |
| DDR400 | Corsair CMX512-3200XLPRO
2x 512 MB DDR400 (200 MHz, CL 2.0-2-2-5 1T) |
| Common Hardware | |
| Graphics Card (PCIe) | MSI NX7800GTX-VT2D256
GPU : Nvidia GeForce 7800GTX (430 MHz) Memory : 256 MB GDDR3 (1200 MHz) |
| Hard Drive I | SATA Western Digital WD740
74 GB, 8 MB Cache, 7200 UPM |
| Hard Drive II | SATA Western Digital WD1600
160 GB, 16 MB Cache, 7200 UPM |
| DVD-ROM | Gigabyte GO-D1600C (16x) |
| Software | |
| Nvidia nForce 4 SLI X16 | Forceware x16 6.85 |
| Nvidia nForce 4 430/410 | Forceware 430/410 8.22 |
| Nvidia Graphics | Detonator 81.98 |
| DirectX | Version : 9.0c (4.09.0000.0904) |
| OS | Windows XP, Build 2600 SP2 |
Benchmarks And Settings
| Benchmarks and Settings | |
|---|---|
| OpenGL | |
| F.E.A.R | Version : 1.0
Resolution : 1280x960 Computer : High Graphics Card : High Options-Performance-Test settings |
| Quake 4 | Version : 1.0.5 Beta (Dual-Core Patch)
Resolution:1280x1024, High Quality Timedemo demo4.demo 1 (load textures) |
| 3DMark06 | Version 1.0
Resolution : 1024x786, 32 Bit Graphics and CPU Default Benchmark |
| Video | |
| Mainconcept MPEG Encoder | Version : 1.5.1
1.2 GB DV to MPEG II (720x576, Audio) converting |
| Pinnacle Studio 10 Plus | Version : 10.1.2.2150
from : 352x288 MPEG-2 41 MB to : 720x576 MPEG-2 95 MB Encoding and Transition Rendering to MPEG-2/DVD no Audio |
| TMPEG 3.0 Express | Version : 3.0.4.24 (no Audio)
182 MB VOB MPEG2-source (704x576) 16:9 |
| DivX 6.11 | Version : 6.1 (2 Logical CPUs)
Cerfinition Profile : High Definition Profile Multipass, 3000 kbit/s Encoding mode : Insane Quality |
| XviD 1.1.0 | Version : 1.1.0 Beta 2
Encoding type : Twopass - Single pass Profile @ Level : DXN HT PAL Target size (kBytes) : 570000 |
| Audio | |
| Lame MP3 | Version 3.97 Beta 2 (11-29-2005)
Audio CD "Terminator II SE", 74 min wave to mp3 160 kbps |
| OGG | Version 1.1.2 (Intel P4 MOD)
Version 1.1.2 (Intel AMD MOD) Audio CD "Terminator II SE", 74 min wave to ogg Quality : 5 |
| Applications | |
| Winrar | Version 3.51
(303 MB, 47 Files, 2 Folders) Compression = Best Dictionary = 4096 kB |
| Autodesk 3D Studio Max | Version : 8.0
Characters "Dragon_Charater_rig" HTDV 1920 x 1080 |
| Synthetic | |
| PCMark05 Pro | Version : 1.1
CPU and Memory Tests |
| SiSoftware Sandra 2005 | Version 2005.7.10.60 SR3
CPU Test = MultiMedia / CPU Arithmetic Memory Test = Bandwidth Benchmark |
| Other | |
| Windows Media Player 10 | Version : 10.00.00.36.46 |
Please note that all of our benchmark results were obtained using pre-production processors that did not yet support full DDR2-800 speed. Thus, the results show the basic performance difference between current Socket 939 systems at DDR400 speed and ideal CL2.0-2-2-5 1T timings, versus DDR2-667 at average CL4-4-4-12 timings.
This clearly cannot be seen as a direct performance comparison between the Socket 939 and the upcoming Socket AM2 platform, and does not reflect the final product's performance. Still, the results help us understand that DDR2-800 is required in order to match or slightly exceed the performance levels available with Athlon 64 architecture on DDR400 memory.
OpenGL









Applications







There are a couple of facts that our analysis make clear:
- The Socket AM2 generation is certainly not going to outperform comparable Socket 939 (DDR400) processors at DDR2-667 memory speeds-see our benchmarks. This is why AMD decided to wait for DDR2-800 and launch in June.
- Since the production process is not going to be changed, power consumption and heat dissipation in the mainstream will remain where they are today. We did some basic testing, but as expected the difference was not worth mentioning.
- AMD is going to introduce low-powered processors for power and noise sensitive environments. The single cores will maintain a 35 W power envelope, while the dual cores won't exceed 65 W. The latter is the mainstream thermal design that Intel intends to introduce with its upcoming Conroe processors in Q3. What we find amazing is that AMD must be able to reach these envelopes using its 90 nm technology, while Intel had to switch to 65 nm in order to maintain this course.
- Moving the Sempron and Athlon families to a common socket eliminated the need for separate budget and mainstream/performance platforms.
- The current Socket 754/939 Athlon 64 processors and motherboards usually cannot cope with more than 4 GB of RAM-there are few 2 GB DDR400 DIMMs-although addressing more than 4 GB is technically possible. The Socket AM2 Athlons will be able to use attractively-priced 2 GB DDR2 DIMMs.
- The changed mounting mechanism for the CPU cooler will annoy enthusiasts who spent a lot of money on a sophisticated, motherboard-mounted solution. However, we expect average Joe to be good to go with the boxed cooler or other 3rd party products that certainly won't be more expensive due to this change.
Conclusion

Things are changing quite a bit. First, we have to say that the AM2 platform we received for this quick preview was as stable as a production system - this probably would not have been the case few years ago. Second, it is interesting to see that AMD is ready to launch AM2, and yet it is still waiting for the right moment. DDR2-800 and higher chip densities are a good justification for delaying the launch to late Q2.
Three years ago, AMD could never have afforded to delay a major technology launch for the sake of waiting for the ideal moment (or to make sure the new chips are available in sufficient quantities). Today, the Athlon 64 processor family is widely considered superior, which puts AMD into a role as leader rather than as a struggling competitor.
The Socket AM2 is a generation change that is becoming increasingly necessary for the sake of supporting memory that will be mainstream in mid-2006 and into 2007. It won't change the performance landscape by much, unless AMD decides to make some fundamental changes to the architecture such as upgrading the FX to 4 MB cache. However, it will also be the basis for the upcoming 65 nm processors that are due at the end of this year. That is when things are going to heat up; the shootout between Intel's Conroe desktop processor and AMD's shrunk Athlons will be as hot as the Gigahertz battle in 2000.

