Remember the good old days of about a decade ago when choosing a server processor was much like deciding whether to go with a Cadillac or a Chevy? Since those days, however, Advanced Micro Devices of Sunnyvale, Calif., has come a long way in its quest to catch Intel. In fact, it established a lead in server performance via its Opteron line.
However, Intel Corp. of Santa Clara, Calif., stole the thunder back by being faster off the mark with quad-core Xeons and has remained ahead for the best part of a year. That may be changing, though, with AMD's recent announcement of an entire line of quad core processors.
So who's ahead, who's lagging, and which is best for what workloads?
AMD's New Line
There are currently nine quad-core AMD models available today the processors are perhaps better-know their codename, Barcelona. In the two-socket space, the AMD Opteron processor Model 2347 runs at 1.9 GHz and Model 2350 runs at 2 GHz. Both operate in AMD's mainstream 75 watt thermal envelope. Additionally, there are three AMD Opteron 2300 Series processors in the highly efficient (HE) 55-watt bracket; Model 2347 HE runs at 1.9 GHz, Model 2346 HE which runs at 1.8 GHz, and Model 2344 HE which runs at 1.7 GHz.
For the four-socket space, there is Model 8350, running at 2 GHz and Model 8347 running at 1.9 GHz and 75 watts. There are also two HE parts for four-socket servers: the Model 8347 HE, which runs at 1.9 GHz, and Model 8346 HE, which runs at 1.8 GHz.
"The HE processors offer superior performance-per-watt, ideal for rack-dense or blade environments, and the standard segment offers compelling price points for excellent performance and performance-per-watt," said Bob Brewer, chief vice president for marketing and strategy at AMD.
AMD touts the improved energy efficiency of Barcelona. Power-saving enhancements include the capability to turn off portions of the processor logic and memory controller when not in use and help to reduce processor energy consumption and heat generation. In addition, each core's power utilization can be separately controlled for better power management.
The company also pushed what it terms "native" multi-core technology with Direct Connect Architecture. This allows the processors to be connected directly to one another and an I/O and memory controller to be directly connected to each processor.
AMD's view is that Intel's Xeon is multi-chip module or two dual-core processors glued together and that is legacy front-side bus architecture introduces bottlenecks in memory-intensive applications. AMD claims that Barcelona is the only true quad-core design. Gordon Haff, an analyst with Illuminata Inc. of Nashua, N.H., agrees that the current Intel quad-core chip, code named Cloverton, is not a 'pure' quad-core design like AMDs.
"Cloverton is essentially two dual-core 'Woodcrest' designs, each on its own die, connected within a single package," said Haff. "In general, you'll see less performance from this type of design than one designed from the ground up for quad-core. Cloverton's 50 percent or so performance jump relative to a comparable dual-core is a solid boost but not what could be delivered by the most optimized design."
While AMD has 2-way and 4-way quad-core models, Intel has 1-way, 2-way and 4-way. Most recently, the company unveiled a new 4-way portfolio designed for multi-processor servers running applications demanding high performance, reliability and scalability. The six new quad-core Xeon 7300 series processors codenamed Tigerton can deliver more than twice the performance and more than three times the performance per watt over the company's previous generation dual-core products.
As well as twice the cores, the 7300 series offers up to four times the memory capacity of Intel's previous Multi Processor (MP) platforms. It includes frequencies up to 2.93GHz and power ratings of 130 watts, 80 watts and 50 watts. The 7300 chipset enhances data movement between the processors, memory and I/O connections.
Intel is attempting to make a big deal out of Tigerton's virtualization capabilities. Users can tie all of their server resources, whether they are single-, dual- or multi-processor based, into a virtual server infrastructure that allows live virtual machine migration. This is said to improve failover, load balancing, disaster recovery and server maintenance. In keeping with this, the company has been partnering with VMware to optimize VMware ESX Server on the Xeon 7300.
"Tigerton more prosaically the Xeon 7300 gave Intel a performance-competitive four-socket product for the first time in several years," said Haff.
So how does it stack up against AMD's latest announcement?
"Yes, AMD does have integrated memory controllers (for getting data from memory more quickly) and a single-die quad-core design (for faster communications between cores) whereas Intel creates a module using two separate dies in a single package," Haff said. "However, for the most part, Barcelona's design features don't deliver the 'knock them out of the park' performance gains that AMD's Opteron had relative to older Intel designs."
He characterizes the new generation of AMD processors as being competitive with Intel's products better in some ways, perhaps not as good in others. With floating point performance and other technical workloads, Haff said he believes AMD has an advantage. Technical shops such as Lucasfilm and the Texas Advanced Computing Center, for example, are big fans of Barcelona.
Another area of potential strength for AMD is virtualization technology. AMD claims its chips are 79 percent better on VMware than Intel. However, Intel makes a similar claim. Both sides provide benchmarks to indicate their own strengths as well as the weaknesses of the competition. But it's hard to separate, at this juncture, the fact from the fiction.
And whatever AMD says about the purity of quad-core design has to be tempered by the fact that it is currently out-gunned by Intel in terms of raw frequency 2 GHz for Barcelona compared to up to 3 GHz for some Xeon quad cores. Note, though, that AMD plans to boost performance by the end of the year."We expect to ramp Quad-Core AMD Opteron processors to higher frequencies of 2.3 GHz and above in Q407," said AMD's Brewer.
So at the end of the day who's ahead? It's probably still too early to tell. Users are best to test both processors in their own environments to determine if one or another product provides a discernible advantage.
"We continue to see AMD and Intel leapfrogging one another," said John Enck, an analyst at Gartner Inc. of Stamford, Conn. "We don't see where either vendor has a long-term technology advantage over the other when it comes to multi-core implementations."
Quad-Core Server Processor Snapshot
|AMD Opteron 8300||1.8-2.0 GHz||55-75 watts||2 MB L2 and 2 MB L3||4|
|AMD Opteron 2300||1.7-2.0 GHz||55-75 watts||2 MB L2 and 2 MB L3||2|
|Intel Xeon 7000||1.6-2.9 GHz||50-130 watts||4-8 MB L2||4|
|Intel Xeon 5000||1.6-3.0 GHz||50-120 watts||8MB L2||2|
|Intel Xeon 3000||2.13-2.66 GHz||95-105 watts||8MB||1|