Summary: After launching their server and workstation-oriented dual-core Opteron processors last month, today AMD is allowing the press to release benchmarks on their dual-core desktop "X2" Athlon 64 processors, which will be available starting in June. See how the new processor stacks up to the latest single and dual-core processors from both AMD and Intel, as well as overclocking results with our Athlon 64 X2 4800+ chip inside!
Fortunately, we didnít have to wait long. AMD maintains that it isnít officially launching the Athlon 64 X2 family until sometime in June; however, itís more than happy to provide a sneak peak at the hardware to tide us over for the next month. Could it be that AMDís worried about Intelís aggressive dual-core price structure? Thereís little reason to be. Announced more than a month ago, thereís still no evidence of a boxed dual-core product from the Pentium D or Extreme Edition families. In fact, the only readily available dual-core hardware currently selling is AMDís Opteron 800-series.
We can nevertheless understand AMDís urgency. Whereas the server and workstation markets stand to benefit immediately from threaded software, Intel is effectively getting the word out that dual-core will improve multi-tasking performance on the desktop as well, even when youíre talking about single-threaded programs. AMD wants in on the action and is ready to position its dual-core Athlon 64 X2 in what it calls the prosumer (proactive/professional/prosperous consumer?) and digital media segments populated by sophisticated power users and content creation enthusiasts.
Availability is the sticking point. Donít expect an encore to the wonderfully executed Opteron launch last month. This time around AMD is pre-announcing its product, launching sometime in June, delivering availability to system builders in the third quarter, and enabling retail availability sometime later. The road to dual-core will be an arduous one littered with temptation (thereís an Athlon 64 FX update coming later this year), competition (those dual-core Pentium Dís sure are priced to move), and financial hardship ($1,001 for an Athlon 64 X2 4800+? Ouch!). Letís see if the nail-baiting is justified.
Examining the Athlon 64 X2
As with the Opteron, both processing cores interface with a request queue and crossbar thatís responsible for delegating communication between cores, the memory controller, and the HyperTransport bus. Of course, a single-socket Athlon 64 X2 doesnít have the throughput requirements you might otherwise see on an eight-way server, so thereís only one HyperTransport link running at 1 GHz. The benefit of AMDís approach is clear--with each core communicating at full-speed, the overall gains realized by threading increase and the scaling characteristics of future processors are more likely to remain linear.
One of the ways AMD plans to differentiate various X2 models is through cache size, as it does currently. All Athlon 64 X2 processors include 64KB of L1 data cache and 64 L1 instruction cache per core, for a total of 256KB. Additionally, some will feature 512KB of L2 cache per core, while others wield 1MB per. By individually tweaking operating frequency and cache size, AMD is able to establish variability in performance and price.
Take the Athlon 64 X2 4800+, for example. Operating at 2.4 GHz and equipped with 1MB of L2 per core, the 4800+ defines AMDís uppermost dual-core offering. A 4600+ will fall right below it, also running at 2.4 GHz with a reduced 512KB per core. The 4400+ ratchets L2 capacity back to 1MB, but drops clock speed to 2.2 GHz. Finally, the 4200+ will offer 2.2 GHz and independent 512KB caches.
In other environments where multi-tasking might be more heavily emphasized or where encoding tasks employ the two cores simultaneously, AMDís naming scheme makes a lot more sense. Itís entirely plausible that an X2 4200+ would outmaneuver a single-core 4000+ in Windows Media Encoder 9, despite the loss in cache and frequency. Naturally, as time progresses and more software developers show favor toward threading, that gap will increase toward dual-core. For the time being, though, how much of an advantage a dual-core processor retains over a single-core chip remains a function of how itís used.
Microsoft Windows Media Encoder 9
We see some pretty amazing results in Media Encoder 9 with the Athlon 64 X2 4800+ running at an aggressive 2.4 GHz and complemented by aggressively tuned DDR400 memory. Not only does the chip simply trounce every single-core offering from AMD (including the 2.6 GHz Opteron 252, but it also blows right past Intelís dual-core Extreme Edition 840. It even cruises on by the Opteron 875, a dual-core chip running 200 MHz slower. The 4800+ very nearly halves the encoding time of AMDís FX-55.
The first half of Futuremarkís 3DMark05 metric is designed to measure graphics performance. It isnít optimized to highlight dual-core processing and as such doesnít demonstrate an appreciable gain. The single-core FX-55 and Opteron 252 processors hold the edge with little effort when frequency matters most.
Maxon Cinema 4D Cinebench 2003
id Software Doom 3
Intelís own documents list Doom 3 as a single-threaded app incapable of exploiting dual-core benefits. Nevertheless, at high resolutions, processor performance isnít holding us back, anyway. Even if Doom 3 were optimized for multiple threads, the X850 XT in our test bed is the bottleneck.
Valve Half-Life 2
AMD makes no false claims when it comes to dual-core and gaming. The 2.6 GHz Athlon 64 FX-55 maintains its edge in Half-Life 2. On the other hand, even the dual-core Athlon 64 4800+ enables impressive numbers compared to any of Intelís offerings. As the resolution increases and processor performance plays second fiddle to graphics capability, the gap between single-core and dual- shrinks even further. Given the numbers at 1600x1200, itís definitely worthwhile to give up five frames for the processing horsepower enabled by dual-core.
Another preconception we had was that because a dual-core Athlon 64 is so complex, to the tune of 233 million transistors, overclocking would be severely disappointing. To the contrary, we hit 2.7 GHz and managed to get it stable at 2.64 GHz. While not monumental by any means, the ability to pace the fastest gaming chip on the market and enable the absolute best threaded performance currently available makes the 4800+ a valuable jewel indeed.
The real sticking point is going to be availability. AMD is claiming that product will be out there by June, but primarily through system builders. And even then, European markets may see more dual-core than North America. Current indications suggest it could be Q4 before the do-it-yourselfers see any significant number of Athlon 64 X2 processors with which to play. The true irony here is that AMD prides itself on stifling announcements until itís ready with the hardware to satisfy demand. This time around, thereís no room to point fingers. At least the dual-core Opteron 800-series was ready as planned, right?
So, at the end of the day, AMDís dual-core desktop chip offers the most elegant design, the smoothest upgrade path, and without question, the best performance. Thereís an excusable compromise in non-threaded performance to go along with the jump in multi-tasked and multi-threaded speed, too. AMD knows it has the upper hand here and is asking a premium price in response. Whether or not you bite will depend on how much youíre willing to spend. If it turns out that the Athlon 64 X2 4400+ overclocks beyond the 4800+, enthusiasts will likely take notice. Then again, AMD has to make the processors available first. When it does, even gamers should get excited about this one.
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