Windows 7 will be will be a major release, Microsoft CEO Steve Ballmer claimed on Thursday. It will be like Windows Vista, but more so.

“[I]t’s Windows Vista, a lot better,” said Ballmer during a Q&A session hosted by Gartner analysts at the research firm’s annual Symposium ITxpo in Orlando, Florida.

Gartner’s Neil MacDonald asked how Microsoft would walk the line between doing too much with Windows 7, risking the kind of compatibility problems that haunted Vista early on, and too little, which might give potential buyers an excuse to avoid the upgrade.

“Windows Vista is good, Windows 7 is Windows Vista with clean-up in user interface and improvements in performance,” Ballmer said. “Look, I’m not encouraging anybody to wait, I’d go ahead and deploy it right away. We didn’t have to go in an incompatible direction to make big strides forward. It’s a real release, because it’s a lot more work than a minor release. It turns out you can do more than just a minor release in what is essentially a two-and-a-half year period of time. There’s no reason to do just, quote, a minor release, in two-and-a-half years.”

On Tuesday, Mike Nash, Vice-President of Windows product management, said Windows 7 was the product’s official name. He called the operating system “evolutionary” but still a “significant” advancement. “It is in every way a major effort in design, engineering and innovation.”

Ballmer defended Vista’s first two years in the market, claiming that it has 80 million users. He understood that companies might decide to skip Vista and move straight from Windows XP to Windows 7. “If people want to wait, they certainly can,” he said.