As reported in Feb, 2004, Microsoft developed XBOX 2 on PowerMac G5s: ...from: http://www.theinquirer.net/?article=14407 Xbox 2 SDK released on cool Apple Power Mac G5s

By Paul Dutton: Saturday 28 February 2004, 15:59

WE'VE JUST got word that the Software Development Kit (SDK) for Microsoft’s forthcoming Xbox 2 has now been released to Developers. As we reported earlier, IBM processors are indeed the Xbox 2 development platform of choice. The big news to us is that the XBOX 2 SDK has been seeded to developers on dual Apple Power Mac G5 systems running a custom Windows NT Kernel. [...]

..from: http://news.com.com/Xbox+360+demos+hanging+from+Apple+tree/ 2100-1043_3-5706658.html?part=rss&tag=5706658&subj=news

Xbox 360 demos running on Macs Published: May 13, 2005, 2:11 PM PDT By Richard Shim Staff Writer, CNET News.com The nifty clips of video games [shown during a pre-taped MTV broadcast on Thursday night] supporting Microsoft's new Xbox 360 console are running on Apple machines, Microsoft confirmed on Friday.

"We purchased a number of Apple G5's because very specific hardware components of the G5 allow developers to emulate some of the technology behind future Xbox products and services," a Microsoft spokesperson said in a statement. "This is an interim development tool that will be replaced with a more powerful and comprehensive solution later."

The current systems shown at product introductions are prototypes. Final systems are expected to come out in all three major regions-- North America, Europe and Asia--by the end of the year.

The prices for the new consoles have yet to be announced, but executives have said they won't be released until after the E3 game conference in Los Angeles next week.

Some details have been released on the new console, such as its 20GB hard drive, DVD-ROM drive and 500MHz ATI graphics processor, but others will be announced during the conference. Executives have said that up to 40 titles for the Xbox 360 will be announced by the end of the year.

The new console from Microsoft is based on a similar IBM PowerPC architecture used in Apple computers--the Xbox 360 uses three 3.2GHz symmetrical cores, according to the company. Apple has been using PowerPC chips since 1994 and Apple Chief Executive Steve Jobs has said the company is happy with IBM's PowerPC family of chips.

Microsoft recently switched processors from an Intel chip used in the first Xbox console to a custom Xbox processor based on Big Blue's Power technology in its new Xbox 360.