As the troubles with Sudderth's shows, however, just because an instruction was supported 10 years ago doesn't mean it was ubiquitous 10 years ago. The Intel DP35DP was released six years ago, and the Core 2 family of processors was extremely popular.
"It's frustrating that an older but robust machine—one that can play modern PC games and run Windows 8 flawlessly—can be left behind after what is essentially a service pack release," Sudderth says. Other forum-goers echo the same irritation. "I hope that I'm a rare exception, but I'm also concerned that Windows developers will target Windows 8.1 and leave me behind just as Microsoft did."
The newly released modern UI Facebook app, for example, only runs in Windows 8.1.
More worrying than that, however, is Microsoft's plan to discontinue support for Windows 8 "vanilla" after 2015. Beyond then, you'll need Windows 8.1 installed to receive security patches and other updates.
What can you do if you're affected?
If you're stranded on Windows 8 and don't want to buy a new machine—and why would you if it still rocks Battlefield without skipping a beat?—all might not be lost.
The CMPXCHG16b requirement only applies to the 64-bit installation of Windows 8.1; the 32-bit version should work just fine on your machine. (I say "should" because I haven't been able to try it.) Now for the bad news: There's no way to use the free Windows 8.1 update to downgrade from 64-bit to 32-bit, even if you try workarounds that skip the Windows Store and let you burn the update to a flash drive. You'd have to buy the 32-bit OEM version of Windows, which starts at $100, and do a fresh install. (Again: That's in theory. I have not been able to confirm this.)
Now read: PCs left unprotected as ZoneAlarm, Comcast's Norton struggle with Windows 8.1
Or you could call Microsoft support and complain loudly enough to try to get a free copy. Because to be left marooned by shifting hardware requirements in a "point" update, with no way to downgrade to a compatible version and the threat of discontinued support lingering, is absolutely ludicrous.
I'll let this irritated forum-goer have the last word: "It's just amazing how Microsoft chooses to leave some of its users hanging out to dry because of these CPU related requirements."
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