The performance gap between PowerPC and x86 is "not a myth," according to Mac and Windows gaming developer John Carmack, cofounder of id Software. Mr. Carmack made the comment at Slashdot in response to a discussion there about Fridayis Devilis Advocate column by John Kheit at The Mac Observer. According to Mr. Carmack, the compilers available for PowerPC on the Mac platform are simply not as fast as those available for Windows.

The comments came in reaction to John Kheitis suggestion that some game developers may leave Mac on PowerPC behind in favor of Mac on Intel, once Apple completes its migration to Intelis processor family. While Mr. Carmack did not endorse that idea, by any means, he did stress that higher performance is currently available on Windows and x86 than on Mac and PPC.

"We work with Apple, ATI, and Nvidia to make everything run as well as possible," wrote Mr. Carmack. "Doom 3 had AltiVec code in it, and there were driver changes to make things work better. The bottom line is that the compiler / cpu / system / graphics card combinations available for Macs has just never been as fast as the equivalent x86/windows systems."

He added, "the performance gap is not a myth or the result of malicious developers trying to make your platform of choice look bad."

Market reality, however, is the real enemy for developing the fastest Mac on PowerPC application.

"Yes, it is always possible to make an application faster," wrote Mr. Carmack, "but expecting developers to work harder on the Mac platform than on windows is not reasonable. The Xbox version of Doom required extensive effort in both programming and content to get good performance, but it was justified because of the market."

"In hindsight," he added, "we probably should have waited and ported the Xbox version of the game to the Mac, which would have played on a broader range of hardware. Of course, then we would have taken criticism for only giving the Mac community the icrippled, cut down versioni."

Mr. Carmack has long been a supporter of the Mac platform, appearing at several Macworld Expo keynotes alongside Steve Jobs showing off id games to the Mac audience. He has also personally worked on such things as keeping the Mac and Windows versions of Quake Arena code-compatible, and releasing the Mac and PC versions of that game simultaneously in 1999.

At that time, Mr. Carmack said, "thereis no reason why the Macintosh canit be a perfect gaming platform."

According to his more recent comments, however, the reality today is that some things are not as good for gaming on the Mac platform as they could be.

Mr. Carmackis roots in the Mac OS X world extend back to NeXTSTEP, as it was a NeXTSTEP box on which he developed the original Quake game.