Stacking Up New Power7 Against Power6/6+ Blades

April 26, 2010 Timothy Prickett Morgan

Major Correction: In this story, I thought the price to activate either i 6.1 or i 7.1 per core on the new Power Systems 701 blade server was $2,250 a pop plus $250 per user, as it is on the Power Systems 700 blade, since both are single-socket blades. Nope. The PS701 blade has the same ridiculous price as the two-socket PS702 blade. So my analysis below is for the PS701 is not correct. I have updated this analysis and the price/performance table in the May 10 issue, which you can read here.

When IBM announced the new Power7-based blade servers on April 13, it was pretty obvious from the get-go that the Power7 blades would pack a lot of processing oomph compared to the Power6+ blades–the JS23 and JS43–that they replace. Like around three times the oomph and twice the main memory per blade. This is a great testament to Moore’s Law.

And as I pointed out in my original discussion of the hardware, the price of the hardware for a heavily configured single-wide Power Systems 701 or double-wide Power Systems 702 blade went up were such that the bang for the buck, as gauged by IBM’s Commercial Processing Workload (CPW) online transaction processing benchmark test, improved by an even greater margin over the single-wide JS23 and double-wide JS43 Power6+ blades that came out last year.

Again, this is all good. But, but, but. As I cautioned at the end of my initial analysis of the new blades on April 13, the hardware costs can be overwhelmed by the costs of the systems software and other elements of the system you need to add, such as a blade chassis, SAS controllers and disks, and a reasonable tape drive for archiving data and getting i 6.1 or i 7.1 on a box. And, after ginning up a bunch of comparisons with the old JS12 and JS22 Power6 blades (the original Power-based blade servers from April 2008) and with the JS23 and JS43 Power6+ blades, this has indeed turned out to be the case for many configurations. And, the very generous pricing on the JS12 blade, which includes one core of i 6.1 or i 7.1 activated on the box in its base price, makes it a very tough box to beat when it comes to bang for the buck on a configured blade box.

That said, as you can see from the Power Systems i blade server comparison table I have made, which put these blades into a BladeCenter S chassis with SAS disk modules for extra storage and an LTO-3 generation tape drive, the entry PS700 blade, which is restricted to four Power7 cores and eight DDR3 memory slots is yielding about the same bang for the buck on a configured system. (The Power7 machines have more base memory in them.) The table also calculates the cost per user for the typical number of users a machine is set up for, based on the user-based pricing bands IBM set up for i5/OS several years ago. Sometimes, companies buy a machine for raw performance, sometimes they buy it for a set number of users, so my comparisons let you look at the value of a given machine either way.

On a cost per user basis, since it costs $26,617 in a configured setup with one of its four cores dedicated to i 7.1, 8 GB and eight disks, the PS700 entry Power7 blade costs a lot more for 10 users than a JS12. The PS700 is pricey compared to a JS12 because it costs $2,245 per core to put i 6.1.1 or i 7.1 on each core, instead of having it bundled on the one core for free as the JS12 does. And the Power6+ JS23 blade was a lot more pricey than the PS700 because that machine had an i 6.1 (and now i 7.1) license cost of $14,995 per core. All the machines require a user license that costs $250 per seat atop these per-core license fees; this per-seat charge also applies to the JS12 from two years ago, which by the way, you can still buy if that is all you need.

What the table I built really shows is how the JS23 and JS43 from last year were way overpriced and offered much worse price/performance than the JS12 and JS22 blades they replace, even as they offered a lot more scalability. (In the table, a negative price/performance rating means that is how much worse of a deal the boxes were compared to the JS12 or JS22 that they are configured to most resemble.)

With the Power7 blades, the operating system costs $2,245 per-core on both the PS700 and the PS701, and you have to move up to the double-wide PS702 before you get whacked by that $14,995 per-core license fee that made the JS23 and JS43 so expensive. Many customers have been clamoring for that change in licensing, which makes blades more palatable because they are crankier for i shops to set up than rack and tower machines thanks to the Virtual I/O Server that is required on the blades for running i 6.1 or i 7.1.

While the PS700 has trouble stacking up against the JS12, the PS701 has no trouble at all beating the JS22 from 2008 and whips the tar out of the JS23 with similar configurations. That’s whether you are talking about supporting 40, 80, 150, or 300 users, or if you are just looking at the price for a unit of raw processing capacity when the number of cores shown are running an i operating system.

The table also shows that the top-end blade keeps getting more oomph as each year goes by, and that top-end blade keeps getting cheaper. The JS22 blade with 32 GB and four 4 GHz Power6 cores activated costs $142,420 all configured up to do real work, which is $1.04 per transaction per minute or $475 per user assuming 300 users. That machine was rated at 13,800 CPWs, which I reckon works out to about 137,310 TPM on the TPC-C online transaction processing benchmark. (Those are my estimates, and they are conservative without the kind of gaming that a lot of other platforms do.)

Jump to the biggest blade in 2009, the JS43. With eight 4.2 GHz Power6+ cores, this double-wide blade was rated at 24,050 CPWs, or about 239,300 TPM; with 128 GB of main memory and a slew of disks, plus i 6.1 on all the cores, this machine cost $262,405. That’s almost twice the money for less than twice the work, and hence it offered a little worse bang for the buck at $1.10 per TPM; assuming 300 users, that works out to $875 per user. Now zip ahead to 2010 and the double-wide PS702. Turn all 16 cores on and slap i 7.1 on them and you get a machine with 76,300 CPWs (just over 759,000 TPM I guess), and it will cost you $384,531 with 256 GB of memory and a bunch of SAS disks. For 300 users, you are talking $1,282 per user, but on an OLTP basis, you are talking about 51 cents per TPM.

That’s as good on a per-unit of work as the JS12. And that is saying something.

Now, I need to figure out how these new blades stack up against Windows, Linux, and Unix blades. Stay tuned.

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