None of the vendors have a lot to cheer about, at least when it comes to Unix: Unix systems revenue dropped 20 percent in the June quarter, to $2.3 billion, according to recent figures from IDC. But at least IBM's revenue declined only 10 percent, and it managed to gain 6.1 points of market share, IDC said.

The Power7+ is being offered now for the Power 770 and 780 systems, which sit near the high-end of the Power line-up. It will come eventually to lower-end systems as well, like the 740 and 750, but IBM isn't saying yet when that will be.

IBM's most powerful Unix machine, the Power 795, won't get the new chip at all, Sharma said. Customers that buy such high-end systems generally prefer stability to incremental upgrades, he said, adding that IBM took the same tack when it introduced the Power 6+.

The 795 will get at least one technical boost, however. IBM is introducing a new memory module with twice the density, so the maximum configuration for the 795 increases from 8TB of main memory to 16TB. The 770 and 780 also get the denser DIMMs.

IBM is also introducing a new memory compression accelerator that can "make a 32GB system look like a 48GB or 64GB system," Sharma said. That can help reduce memory costs for customers, but there's a trade-off in increased latency as data is decompressed for use.