IBM Announces PowerPC 970 Blade Server

by Timothy Prickett Morgan

Seeking to halt all the murmuring about its future Power-based blade servers, IBM this week announced the product and set a shipment date of March 5, 2004 for the blades. The new blades, which will plug into the existing BladeCenter chassis, represent the first non-Intel blade server that IBM will put on the market.

The BladeCenter is a 7U form-factor chassis that can house up to 14 two-way server blades, yielding a total of 168 processors in a standard 42U rack. The chassis has an internal Gigabit Ethernet backplane that the blade plugs into, and also includes Ethernet switches and, in the future, will have Fibre Channel and InfiniBand switches as options. The existing BladeCenters have used the H20 blade, which is based on the ServerWorks Grand Champion-LE chipset and which can have one or two "Prestonia" Pentium 4 Xeon DP processors, which are equipped with 512 KB of integrated L2 cache memory and which run at speeds ranging from 2 GHz to 3.2 GHz. The HS20 blades, which supports from 256 MB to 4 GB of main memory, costs $2,009.

The new JS20 Power blade is based on the 1.6 GHz variant of the PowerPC 970 processor that Apple is using in its latest G5 Macs. The blade is based on an IBM Power chipset, which is very likely a derivative of the chipsets it has for its pSeries Unix server line. The PowerPC 970 chip is itself a derivative of the Power4 processor, except that it is single core implementation with all of the interconnection technology and other electronics necessary for a big SMP server removed. (In this regard, it is like the difference between a Pentium 4 Xeon DP chip for an entry servers and a Pentium 4 Xeon MP processor for midrange servers.) The PowerPC 970 chip also has 162 SIMD instructions that were not on the Power4 chip that will make it run like a top on numerically intensive jobs.

While the PowerPC 970 scales up to 2 GHz, IBM is coming out the door with slower chips in the JS20 blade server. The reason is probably not heat related, however, since a Pentium 4 Xeon DP running at 3 GHz cranks out about twice as much heat as a 1.6 GHz PowerPC 970. If anything, IBM should be able to get even faster PowerPC 970s into the BladeCenters. My guess is that IBM has yield issues on the PowerPC 970 chips, and Apple has dibs on the fast ones.

In any event, on infrastructure workloads or jobs that have a big numerical component, even the slower PowerPC 970 should be able to give a Xeon DP processor a run for the money. Why IBM has decided that it can charge $2,699 for the JS20 Power blade (with only a single processor) is a mystery. That's less performance than a Xeon DP blade for more money, and that doesn't make a lot of sense.

The name of the product is significant, perhaps. If the HS20 is a 32-bit Intel Pentium Xeon product, and the JS20 is a PowerPC 970-based product, then presumably there is an IS20 product. That could be a blade server based on the 64-bit Opteron processor from Advanced Micro Devices, or it could be a blade based on the 64-bit Itanium 2 "Deerfield" processor from Intel. Or it could mean nothing. Then again, the JS20 blade server has a memory controller that feeds into a HyperTransport channel, which in turn connects to two IDE channels for disks and six USB channels for other I/O devices. The use of HyperTransport suggests that an IS20 blade, if one exists, is an Opteron machine.

The JS20s running AIX or Linux will be able to sit side-by-side with HS20s running Windows or Linux in the same BladeCenter chassis. However, don't get too excited about AIX support just yet. While the blade will be out in March, IBM says that it will not have AIX ready for the JS20 blade until the third quarter of 2004. Why will it take so long, you ask? I dunno, expect that it is probably the case that IBM had not planned to support AIX on the PowerPC 970 as it was creating it for Apple, and only the advent of the blade server market has made it rethink the idea and actually commit to launching a product. IBM has warned customers that any AIX applications that were compiled with Power4-specific or PowerPC-specific (meaning IBM's Star series of PowerPC chips) will have to be recompiled to run on the PowerPC 970 processors. The JS20s will be able to support Linuxes from SuSE and TurboLinux starting in March 2004, and will presumably support Red Hat's Linux at some point in the future.