IBM Doubles Up Power7 Blade Sockets, Cranks Power 750 Clocks

April 18, 2011 Timothy Prickett Morgan

You were probably wondering like I was last year why IBM only announced Power Systems blade servers using the Power7 processors with single-sockets instead of also offering more dense configurations with two sockets per blade. Big Blue never explained this, but now, one day shy of a year later, the company has put two-socket blade servers into the field. The company has also cranked the clocks a little bit on the Power7 processors used in the four-socket Power 750 midrange workhorse servers.

According to Steve Silbey, who is director of product management for the Power Systems line at IBM, the yields on the Power7 chips are better than they were back in February when the initial Power 750 servers were launched, and therefore IBM can now offer customers faster processors for the same dough on the Power 750 boxes. This processor bump brings the Power 750 into alignment with the faster Power7 options that were available in the Power 710, 730, and 740 machines that were announced last summer.

The new blade servers, on the other hand, will actually be sporting slower, not faster, processors but will be doubling up the number of cores and threads that each blade can handle. Such cores do not make a lot of sense on machines where each core has its own software license for an operating system and system software stack–for instance, with IBM i 6.1 or 7.1, unless you are using the Application Server variant to support the application tier and putting the database on faster processors. But for many workloads, core and thread count is as important as clock speed, so doubling up the sockets makes sense. Particularly for an IBM that just saw Intel cram 10 cores and 20 threads into a “Westmere-EX” Xeon E7 socket last week and with AMD putting a dozen cores (with only one thread per core) into a “Magny-Cours” Opteron 6100 processor socket. There is a core war going on out there in the data center, and IBM was at a socket disadvantage with the current PS701 and PS702 blades.

IBM has announced two new blade servers, and they are very similar to the PS701 and PS702 blades that they augment–but do not replace–in the Big Blue catalog. The PS703 blade server is a single-wide, full-height blade that plugs into a BladeCenter H, HT, or S chassis. The blade, product number 7891-73X, comes with two eight-core Power7 chips running at 2.4 GHz rather than the 3 GHz speed used last year’s PS701 and PS702 blades. By turning down the clocks, IBM can keep the heat down even as it adds a second processor socket to the blade, thereby keeping the BladeCenter chassis from igniting into a pretty blue ball of fire. The other feeds and speeds of the PS703 machine are virtually the same as the PS701: It has some for one 600 GB 2.5-inch SAS disk, two PCI-Express daughter cards for peripheral expansion, and supports up to 128 GB of low-voltage, DDR3 main memory running at 1.07 GHz. IBM is supporting a maximum of 8 GB capacity on the memory sticks and is currently evaluating when it might add 16 GB sticks to the blades. Considering that X64 server makers (including IBM) are talking about using 32 GB sticks with the new Xeon E7 processors, and therefore supporting a whopping 2 TB of main memory for a four socket blade, now might be a good time to ratchet up the memory on the Power7 blades.

The PS704 blade, product number 7891-74X, is a double-wide blade that is essentially two of the PS703 blades snapped together to make a server with a single system image for an operating system or hypervisor to frolic on that sports four sockets, 32 cores running at that same 2.4 GHz, and a maximum of 256 GB of memory. Each blade in the double-wide has the same peripheral expansion as in the single-wide, which means the double-wide has two disks and four PCI-Express daughter card slots.

The PS704 is on the left and two individual PS703s are on the right in the picture below:

On IBM’s Commercial Performance Workload (CPW) relative performance ranking for OS/400 and i workloads, the PS703 with all of its 16 cores activated is rated at 64,000 CPWs, while the double-wide PS704 with all of its 32 cores turned on yields 110,000 CPWs. The single-socket PS701 was rated at 42,100 with eight cores running at 3 GHz, so doubling the socket count while cutting the clock speed by 20 percent still yields 66 percent more CPW oomph. This is a fair tradeoff for a lot of workloads, particularly ones running on IBM i Application Server, AIX, or Linux, where the OS licenses are cheap. Er, well, cheaper at least, in the case of Application Server.

IBM is charging $9,551 for the PS703 blade, which comes with all of its 16 cores activated. The PS704 double-wide with its 16 cores activated costs $28,102. An 8 GB memory module (two 4 GB sticks) costs $506, while a 16 GB module (which is a pair of 8 GB sticks) costs $993. You have to pay $60 for IBM to preinstall IBM i on these blades, not counting the IBM i licensing fees themselves. (I have not been able to track down the licensing costs for IBM i on the blades yet.)

IBM is not planning to kill off the PS700 (four cores only), PS701, or PS702 blades from last year, and in fact, it is still selling the single-socket, Power6-based JS12 blade server as its low-cost entry blade, according to Silbey.

More Horsepower for the Power 750 Workhorse

Over on the Power 750, which is overkill for most OS/400 and IBM i shops but which is probably the big RPG or COBOL box for quite a large number of companies, IBM is upgrading the processor speeds on three existing processor modules and adding a new one to the mix.

The Power 750 server design puts a single processor socket and 128 GB of main memory on a single processor module that is, when you look at it, is functionally equivalent to a single-socket PS701 blade server from last year. The Power 750 server can have from one to four of these processor modules, and therefore up to 32 cores and 512 GB of main memory. The 4U rack-mounted chassis has room for eight 2.5-inch drives (they can be hard disks or solid state drives), two media bays, and five PCI slots (three PCI-Express 2.0 x8 and two PCI-X slots, to be precise.

Last year, IBM offered processor cards in the Power 750 that ran at 3 GHz, 3.3 GHz, and 3.55 GHz, with the 3 GHz and 3.55 GHz chips being processors with all eight cores usable while the 3.3 GHz chip was a partial dud with only six working cores. Now, that eight-core, 3 GHz processor option is goosed to 3.22 GHz. This processor module costs $5,940, plus $3,100 to activate each core on the chip. The eight-core, 3.55 GHz chip is now spinning at 3.61 GHz, with the processor module costing $17,700 and core activations costing $9,000. The six-core processor module now has a 3.72 GHz processor, which is a 13 percent increase over last year’s model; the processor module with this 3.72 GHz chip costs $7,000 and each processor activation costs $4,850.

The new processor option on the Power 750 server is a four-core Power7 chip running at that high-end 3.72 GHz speed. The aim here is to give customers who need more memory per core to support their application and databases an option. (Silbey singled out SAP ERP suites as a good example.) The Power 750 processor module using the four-core, 3.72 GHz processor costs $4,310, but oddly enough, IBM is charging a little more to activate each core, at $5,209, compared to the six-core version. Go figure.

IBM will support the i 6.1.1 and i 7.1 operating systems on the new blades as well as its own AIX 5.3, 6.1, and 7.1 Unix releases. Novell‘s SUSE Linux Enterprise Server 11 and Red Hat‘s Enterprise Linux 6 are supported on the new blades and Power 750 processor options, too, just as they are on all Power7-based machines. The new processor options for the Power 750 will be available on May 20, and so will the PS703 and PS704 blade servers.

Next week, I will take a look at how these new processor options and blades stack up in the Power Systems lineup in terms of price/performance.

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