Intel Xeons encroach on PowerPC's territory

Story

September 01, 2006

Intel?s latest crop of desktop and server CPUs might dislodge the PowerPC from embedded applications.

Intel’s latest crop of desktop and server CPUs is not only likely to reclaim the performance crown from rival AMD, there’s also a chance they’ll steal sockets from Freescale’s PowerPC processors in embedded. Long a high-performance favorite for tasks such as control loops and radar processing, the MPC74xx “G4” PowerPC with AltiVec engine has been riding a success curve for more than 10 years. CompactPCI, VME, AdvancedMC, PMC, and other form factor boards rely on the PowerPC more frequently than any other General Purpose Processor (GPP) because of its stellar GFLOP benchmarks in dual- and quad-CPU configurations.

Take a look at just about any DSP board in the market and you’ll likely find a PowerPC (or two) and some kind of FPGA. The current generation MPC7448 PowerPC is just now being deployed, and I’ve reviewed nearly six new product announcements in the past couple of months – from vendors including Aitech, Curtiss-Wright Controls Embedded Computing, Extreme Engineering, and Momentum Computer (affiliated with Mercury Computer Systems). These companies undoubtedly chose Freescale’s latest single core PPC as next-in-line on the PowerPC road map because the current “Book E” Power Architecture scales nicely and allows some form of code migration from earlier versions that date all the way back to IBM’s PowerPC 601.

But this may soon be ancient history because Intel’s dual core Xeon Ultra Low Voltage (ULV) server CPU is offering performance-per-watt numbers that rival the MPC7448. According to Mercury Computer Systems in their recent E-cast “Bringing a Quad-Core Intel Server to Embedded Applications” (www.opensystems-publishing.com/ecast), it’s now possible to stuff two dual-core Xeon ULVs on a single 6U board and still be within easy reach of air- and conduction-cooling. A single Xeon ULV contains two cores running at 1.66 GHz but consumes only 15 W. This compares very favorably to a single core Freescale 7448 running at 1.4 GHz consuming 10 W. In effect, that second core consumes only 50 percent more power.

Moreover, while not really designed for high-end signal processing systems using Symmetrical Multiprocessor (SMP) architectures, two dual-core Xeons – unlike previous Intel CPUs such as Pentium Ms or even Intel’s latest Core Duo CPU – bolt together nicely via Intel’s E7520 Northbridge. According to Mercury, this configuration yields an easily programmed four-way SMP setup with 4x the previous Intel processing density in one 6U slot (see Figure 1). The dual core Xeons share an onboard L2 cache while maintaining good memory bandwidth with off-chip DDR2-400 dual channel off-chip memory. Even better, the Northbridge has ample I/O, including PCI Express, which facilitates handy interboard (or internode) communication. Mercury estimates that the two CPUs, Northbridge, and SDRAM in a four-way SMP architecture would consume a total estimated 75 W on a single 6U board.

Figure 1: two dual-core Xeons – unlike previous Intel CPUs such as Pentium Ms or even Intel’s latest Core Duo CPU – bolt together nicely via Intel’s E7520 Northbridge. According to Mercury, this configuration yields an easily programmed four-way SMP setup with 4x the previous Intel processing density in one 6U slot

What’s the big deal, you say? Existing PowerPC boards consume a bit less power, are ideally suited for SMP, and already have an established code base. That’s true. The big deal is that the ULV Xeon is now squarely in PowerPC territory, and Intel has a road map of additional processors – including quad cores – that stretches out from here to eternity.

Intel is so focused on cranking out more performance-per-watt at commodity prices that embedded designers simply must consider Intel’s offerings as a serious threat to the PowerPC. And when you couple the enormous code base available for Intel Architecture processors, including applications you run on your desktop, CPUs like the dual core Xeon ULV are bound to start showing up in military embedded systems within six months.

For more information, contact Chris at [email protected].

1. This gave rise to Intel’s 16-bit only 80386SX – a low-cost variant that set the stage for modern two-tier flavors such as Pentiums and Celerons.

2. As we went to press, benchmarks for Intel’s very latest Core 2 Extreme processor (code named “Conroe”) have become available. According to Loyd Case of Ziff Davis Media’s ExtremeTech.com, the processor is “crazy fast” and blows most AMD benchmarks out of the water. Similar praise is handed out by Wil Harris at bit-tech.net, a highly respected independent benchmarking website.