AMD's Opteron finds a new gear

How do these numbers compare with results for other processors? AMD’s best submitted SPEC results to date came from a 2.6GHz single-core dual-processor system. For SPECint_rate2000, the older Opteron system scored 40.5; for SPECfp_rate2000 its score was 38.6. For both of these tests the OSes were 32-bit versions of Windows XP Professional or Windows Server 2003. All used Intel’s C++ and Fortran compilers.

Free IT resource Virtualization Insights from Top Experts - Learn how virtualization gets real! Sponsored by Dell Free IT resource Try Sun servers, workstations and storage products free for 60-days. Sponsored by Sun Microsystems Return to special report DOWNLOAD PDF Click here to download InfoWorld's special report Opteron Times Two AMD Opteron 800 Series Advanced Micro Devices, amd.com Cost: 865 (1.8GHz), $1,514; 870 (2GHz), $2,149; 875 (2.2GHz), $2,649; priced per thousand units Platforms: All 32-bit x86 client and server OSes; 64-bit OSes and virtualization environments specially tuned for x64 or AMD64 compatibility Bottom Line: AMD’s dual-core Opteron makes the most of Opteron’s advanced total system design, which leverages independent I/O channels and banks of RAM dedicated to each CPU. Now buyers who weren’t able to step up to quad-CPU servers can buy into them at dual-CPU prices and with no downside.

Intel hasn’t submitted tests for any 64-bit Xeon server CPUs, but I tried to find the best showing among the 32-bit Xeon’s recently published tests. The closest match I found was a Dell dual-processor, single-core, 32-bit Xeon system running at 3.6GHz. The Xeon CPUs in this system had 2MB of Level 2 cache each, compared with Opteron’s 1MB, and the disparity in clock speed (3.6GHz vs. 2.2GHz) should also be noted. Both factors lead to higher system pricing relative to Opteron, and to higher power consumption, heat, and noise. Those factors aside, the 3.6GHz Xeon’s SPECint_rate2000 score was 40.5, and its SPECfp_rate2000 score was 31.7.

Take that, Intel

Complete test results are still to come, but it’s not too soon to know the impact dual-core Opteron should have on customers who have placed their bets on Intel’s Xeon. To be blunt, Intel’s claim of technological parity with AMD is an easily penetrated smoke screen.

If all other technical differences were set aside, AMD’s on-chip memory controllers, dedicated memory banks for each processor, and independent I/O channels among CPUs would decide the battle with Intel’s EM64T. All these features are unique to AMD’s x64 system implementation, and we’ll see them exploited by major commercial OSes and development tools, including Windows Server 2003 x64 Editions and Visual Studio 2005 (currently in beta).

Until Intel delivers its dual-core Xeon, its competitive technology remains Hyper-Threading. Hyper-Threading is an ingenious stopgap that Intel developed to boost the performance of a narrow range of applications, namely those that do their background processing via lightweight threads instead of the coarse processes that dominate software design. Neither the CPU nor the OS prevents threads from attempting to access the same resource, which makes the sloppy use of threads one of the leading enemies of software stability. But even with applications that use many threads, Hyper-Threading delivers, even by Intel estimates, a maximum of about 30 percent improvement to an application’s performance. And these benefits are limited only to heavily threaded applications; Hyper-Threading does not speed up the entire system. In fact, with most systems running a mix of threads and processes, Hyper-Threading can harm performance; a scan of Intel’s SPEC benchmarks reveals that Xeon system vendors often disable Hyper-Threading to improve Xeon’s results.

In contrast to Xeon’s Hyper-Threading, dual-core Opteron is optimized to accelerate the performance of all applications on a system in a fairly uniform fashion. Dual core is an efficient alternative to the common practice of scale-up, which provides a total speed improvement by enabling the server to divide its workload across what amounts to several tightly connected computers. A dual-processor, dual-core Opteron system allows an operating system to distribute its total workload across the logical equivalent of four discrete physical CPUs.

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CPU futures

As with all benchmarks, the results are meaningful only when applied in context, and the only context available here is 32-bit operation. These test results reflect both the advantages and the shortcomings of Microsoft’s first release of Windows XP Professional x64, as well as the effectiveness of dual core. But with all other things being equal -- and they are, given that AMD has packaged dual-core Opteron as a chip upgrade and Microsoft is swapping 32-bit Windows licenses for 64-bit editions -- dual-core Opteron doesn’t merely leave its own predecessor in the dust. It sets a mark for Intel that AMD is certain can’t be met before AMD moves on to better things such as faster HyperTransport buses, still more cores per chip, faster memory, and so on.

Opteron is as close to future-proof as any entry-level 64-bit server or workstation architecture can be. Systems purchased today should still be operating five to seven years from now, with only incremental upgrades through CPU swaps and higher-density RAM (1GB per module instead of today’s 512MB). The dual-core Opteron systems hitting the market this week won’t merely be the best investment in the PC server and workstation spaces. They’re the best bet if you want systems that you won’t have to replace for a long long time.