IBM surprised its mainframe customers and competitors yesterday, saying that it has been able to significantly increase the speed of the G5 mainframes that it announced last May (see Top Stories). The new G5 machines, say IBM, meet or beat Hitachi’s much-loved Skyline processors, which use fast but old-fashioned ECL bipolar chip technology rather than the much cheaper CMOS technology that IBM uses in its 9672 mainframes. IBM has been able to crank the clock speed on its G5 Turbo Symphony 9672 engine to 500 megahertz, giving about 150 MIPS of performance, up from the 125 MIPS it promised back in May. The slower G5 plain-vanilla engine, running at 417 megahertz, yields up 125 MIPS compared to the 115 MIPS IBM was promising. With the Hitachi Skyline rated at between 140 and 150 MIPS, depending on who you ask and how they calculated it, no one is going to be talking about whether ECL is better or worse than CMOS. People will now talk about other things, however, and most of their conversations will revolve around price. IBM is sorely looking for any good news to encourage its mainframe customers to buy something between now and the end of the third quarter. The first two quarters were lean ones for IBM’s mainframe business. In the second quarter, IBM’s mainframe revenue was off 25% on flat MIPS growth compared to last year, which was enough to scare IBM Europe into giving S/390 business partners bonuses if they meet their sales targets for the third quarter, and even bigger bonuses if they exceed them. The improved G5s will make it easier for IBM to raid the Skyline base and to get fence straddlers who might have been considering a Skyline machine to stay in the IBM fold.
By Timothy Prickett Morgan
IBM has already shipped eight G5 machines. Sabre Group, the travel reservation servicing company, was the first customer back in May; since then Allianz, the German insurance giant, ADP, the American data processing services giant, and MCI, the telecoms middleweight, have all taken in G5 machines. By the end of this week, IBM will have installed 16 machines around the world as part of its beta test program. Customers will be able to get their hands on the regular G5 machines, which use the slower Symphony engine and provide from 87 to 877 MIPS using from one to ten processors, starting at the end of August. Machines using the G5 Turbo engines, which have eight, nine or ten usable processors plus extra processors to provide cryptographic processing or to act as hot spares, won’t be available until September 17. These models provide from 915 to 1040 aggregate MIPS. In May, IBM announced a ten-way using G5 Turbo, which was rated at only 900 MIPS, so this is a big improvement (but not as much as one might expect given the 20% increase in raw chip MIPS). Back in May, IBM didn’t have eight-way and nine-way Turbo G5 models, but has subsequently added them to give customers a place to be if they don’t need over a BIPS of power but need the faster individual engines to speed up batch jobs. Model upgrades to G5s from G2, G3 or G4 generation 9672s will be available on these same schedules, but upgrades within the G5 family won’t be available until December 9. Where did this extra power come from? About 8% to 10% of the power increase in the G5 servers comes from the higher cycle times of the chips, according to IBM. Big Blue can crank up the clock speed on the G5s in part because it has external cooling units to keep the chips from frying themselves. IBM is careful to point out that it doesn’t use the complex and costly water-cooling system that its old bipolar mainframes required. The G5s apparently use a plain old refrigeration unit that keeps the chip temperature down to 35 degrees C. The fridge comes from KryoTech Inc. The Turbo G5s are not the first machines to use such a chiller; the RY5 G3 system launched in October 1997 was the first 9672 to use a fridge. Hitachi’s Skylines similarly use chillers.
Manufacturing flaws
IBM got some more performance out of the G5 because the chips didn’t have the usual manufacturing flaws that all chip makers encounter and have to provide software workarounds for – Intel is having such problems with its Xeon Pentium IIs right now. Because the G5 manufacturing process was clean, IBM didn’t have to tweak the G5’s microcode to circumvent errors. Messing with the microcode usually east from 3% to 5% of the power you expect to get from a chip. IBM also included a 5% buffer in its MIPS estimates on announcement day back in May; at the time, IBM had only tested the machines on a few workloads. Subsequently, it has tested the machines on all of its batch, data base, transaction processing and number-crunching test, which are part of the Large Systems Performance Reference (LSPR) suite of benchmarks that IBM and customers use to gauge relative performance and to gin up estimated system MIPS. (You don’t actually think they count instructions, do you?) While the G5s give IBM some breathing room in its captive mainframe market, they don’t make all of IBM’s problems suddenly vanish. For one thing, IBM’s fastest S/390 processors are only available in the 8, 9 and 10 CPU configurations. The SMP models with fewer processors use the slower 125 MIPS chip. Hitachi sells its Skylines across the product line, with from one to eight processors. Moreover, the performance edge IBM has may not hold for long. Hitachi could crank up the clock on Skyline, a boost the company may have been holding back to compete against IBM’s G6 processors, which are due next year. Hitachi needs a 200 MIPS engine, fast, that it can sell at prices that compete with IBM’s G5 and G6. Hitachi obviously knows this, but as usual it is being tight-lipped about its plans. Amdahl is relegated to serving its existing customer base and to trying to beat IBM over the head with its own software pricing schemes with its clever mainframe partitioning. Both vendors can simply throw in the towel and resell IBM’s CMOS S/390 chips in their own system designs. Hitachi already does this, and this may make a lot more sense than getting into a bidding and technology war with IBM over the benefits of IBM CMOS compared to Hitachi’s bipolar ECL. No matter what happens, Hitachi and Amdahl will have to compete against the G5s on price, much as IBM has had to do to win deals against Hitachi with its Skylines. Now with IBM on par with CMOS, Hitachi’s only move until Skyline2 comes out, and maybe even afterward, is to cut prices. This will drive IBM’s prices down, even if there is pent up demand in the part of the mainframe base that is exclusively loyal to Big Blue. The game for IBM is to make as many sales as it can, based on price, MIPS or both, as fast as it can. Because one way or the other, the G5s only have a 9 to 12 month economic cycle and everybody, including Hitachi and Fujitsu, Amdahl’s parent, knows this.
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