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AMD's Opteron 148 and 248 processors

Opteron FX?

IF YOU HAVE BEEN following these things at all, you probably know that AMD introduced its Athlon 64 FX chip last month to great fanfare. This new processor took our benchmark suite by storm, beating out the Pentium 4 3.2GHz by some downright embarrassing margins in many tests. Intel struck back preemptively with its Pentium 4 3.2GHz Extreme Edition, but now that we know that product's actual, heart-stopping price, the P4 EE looks more like a stunt than an actual option for purchase. In my view, the Athlon 64 FX reigns as the fastest x86 processor in the desktop market.

Even so, the Athlon 64 FX and the P4 EE share a common heritage: they are plucked from the top end of each manufacturer's professional workstation/server lineup of chips. Specifically, the Athlon 64 FX-51 is a 940-pin chip nearly identical to an Opteron, with the exception that it runs at 2.2GHz. Before today, the fastest Opteron ran at 2.0GHz. No more. The Opteron 148 chip arrives at 2.2GHz as the workstation equivalent of the Athlon 64 FX. The 248 and 848 models, meanwhile, raise the prospect of servers and workstations with multiple processors¬óchips just like the Athlon 64 FX¬órunning in tandem.


Now, grab your drool rag and ride along as we put the Opteron 148 and 248 CPUs through their paces to see how they measure up as workstation processors.

Introductions and preliminaries
The Opteron 148 is intended for single-processor workstation PCs, while the 248 model can run in pairs. Otherwise, these things are the same basic product: Opterons running at 2.2GHz. They're based on AMD's eight-generation Hammer microarchitecture, with extensions to support 64-bit computing and all the rest. Since the Opteron x48 series is just a speed bump, I won't belabor the point. You can read our introduction to the Hammer architecture here.

I should note a few things, however, before we dive into the test results. First, it really is the case that the Opteron 148 and the Athlon 64 FX-51 are the essentially same product with different names. They both run at 2.2GHz; both nestle into 940-pin sockets; both support dual channels of DDR400 memory. They are, I suppose, aimed at slightly different markets, but both products compete with the Pentium 4, which straddles the high-end desktop and low-end workstation segments. So I dunno. To make things simpler, I've included only one set of benchmarks for the Athlon 64 FX-51 and Opteron 148 chips. You can read the results together, because they perform the same.

Next, the Opteron 146, 148, 246, and 248 chips in our test results all come from systems with DDR400 memory, while the Opteron 140 and 240 setups use DDR333 memory. AMD has been a little fuzzy on DDR400 support in the Opteron line, but the company has now decided to endorse DDR400 officially for the x46 models and above. Of course, Opterons still require registered DIMMs, whatever the speed.

AMD's test kit for the Opteron 148/248 included an MSI 9130 motherboard, a very decent motherboard that we've used in the past for some of our testing. The 9130 is based on VIA's K8T800 chipset, which has proven faster than NVIDIA's nForce3 Pro for most tasks. However, the MSI 9130 has one glaring weakness: it doesn't have DIMM slots hanging off its second CPU socket, so the second processor's built-in memory controller doesn't have access to any local memory. As a result, CPU 1 will always have to go through CPU 0 in order to access memory, and half of our dual Opteron's potential memory bandwidth can't be realized. The MSI 9130 isn't unique in this regard; at present, most dual Opteron workstation boards use this sort of memory configuration.

A pair of Opteron 248s rides atop the MSI 9130

Perhaps it's just as well, because the Windows XP Pro kernel isn't aware of the Opteron's non-uniform memory access (NUMA) architecture, and thus can't take full advantage of an optimally configured Opteron rig. What's more, the 64-bit version of Windows XP has been delayed, so we aren't likely to see a truly optimal version of Windows for the Opteron for quite some time. The Opteron will have to live with some handicaps in our testing, but these are the same handicaps many real Opteron workstations are likely to face.

Speaking of handicaps, the only Intel Xeon chips we've included as foils to the Opteron 248 series run at 2.66GHz with 512K of L2 cache. Nowadays, top workstation Xeons come at 3.2GHz with 1MB of L3 cache. I wish we could have included those chips in our review, but Intel tends not to make its Xeon chips available to the media for comparisons like this one, despite our best efforts. And at about a grand a pop, we're not too keen on buying the latest and greatest Xeons each time we conduct a review. So, uhm, sorry.

As consolation, we've included results for the ultra-expensive Pentium 4 3.2GHz Extreme Edition, which has 2MB of L3 cache, an 800MHz bus, and dual-channel DDR400 memory. This single CPU is even more exotic than the top Xeon workstation chip. So there. We have also included a few other top-end desktop processors, because those chips traditionally bleed into the single-processor workstation segment.

With all of that out of the way, let's dive into the benchmark results, which generally speak for themselves.