Xeon

Posted on 8 Feb 2008 at 12:16

Intel has been no stranger to chip errors and bugs in the past - the biggest being the infamous 1994 Pentium floating-point division bug, which, after a public outcry, forced the company to offer replacements for affected CPUs that had made it on to the market. But none of that has been a problem when it comes to the latest Xeon workstations and server CPUs. We obtained a pair of X5460 Xeons: 3.16GHz, 45nm quad-core parts that are based around the same design as the desktop QX9650 processor, with 12MB L2 cache and a 1,333MHz FSB speed.

Boston tells us it will soon be supplying a version of the 6015B-TV chassis that's able to use the upcoming X5482 and X5472 Xeons, which can run with an FSB speed of a whopping 1,600MHz. In a desktop system, the FSB is almost never fully saturated, but server and workstation workloads that shovel huge amounts of data between main memory and the CPU should benefit.

Power consumption

As it is, the 6015B-TV fitted with a pair of X5460s is quick and, for a rack server, very frugal, too. Populated with just the one Raptor hard disk for the purposes of testing, it consumed only 185W at idle. This rose dramatically to 300W when the system was working hard, but bear in mind that's for eight cores of processing power and 24MB of cache, and not far off 2 billion transistors. Real-world total power consumption is likely to be higher, since the chassis supports four hot-swappable hard drives, but total power consumption should still be below 400W. It's a hell of a lot of computing performance for no more power than a desktop PC with a high-end graphics setup will consume.

One of the criticisms levelled by AMD at the fully buffered FB-DIMM memory required for the 5000P chipset is that its power consumption is unacceptably high, but any hit that the overall power consumption levels take from FB-DIMMs is more than made up for by the performance of the Xeons. In other words, performance per watt is massive even if the memory subsystem isn't the ideal solution when it comes to absolute levels of energy consumption.

Performance

Our standard benchmark suite isn't suitable for testing Xeon performance: the basic server graphics chipset in our test chassis means that benchmarks which intensively update the frame buffer will artificially suffer and skew the results. Instead, we ran a subset of the tests, and for comparison - since quad-core Opteron processors are AWOL - looked at the scores relative to Phenom since it's based on the same Barcelona architecture.

In CPU-intensive workloads such as rendering, the performance is on a similar level to that of the QX9650. But, of course, there are eight cores in total. In threaded applications that really can mean a near-doubling of computing performance. If, when they arrive, quad-core Opterons have performance on a par with Phenom, AMD is going to have a lot of catching up to do.

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Author: David Fearon