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The downside of buying an Intel-based Mac now is that you could become a beta tester for undiscovered--and therefore, yet-to-be-solved--problems. While the transition to the new chip should be smooth for most people, we've noticed that a couple of common problems have cropped up on the message boards since the iMac Core Duo's debut. We've haven't encountered either of these problems during our experience with the iMac Core Duo, but with the number of people discussing these issues online, we wanted to help bring them to light and share the solutions users have found.

Video tearing
The biggest issue so far is a video glitch that appears primarily when using Front Row applications. Users experience video tearing (meaning that sections of video flicker and appear where they're not supposed to), random horizontal lines, and ghosting (a second ghost image of the object on the screen appears next to it). These glitches obscure the image so badly that Front Row becomes unusable. If this describes your experience, don't worry--you're hardly alone.

Apple was a bit slow in addressing this problem, and when we first spoke to Apple PR about it, all we got was, "Apple is aware of this issue and is looking into it. If a customer has any technical issues, they should contact AppleCare." Judging by the comments in Apple's discussion forums, many people did just that but found that AppleCare wasn't much use. Users reported tech support reps who claimed to have never heard of the problem or who weren't given instructions on dealing with it. Some tech support reps asked the callers to return their iMacs for repair and treated the problem as a hardware issue.

Enterprising users, however, discovered that it was a software issue. Apple shipped Intel iMacs running two different builds of OS X 10.4.4; these go by the codes 8G1165 and 8G1171. Nearly all the users experiencing video problems ran 8G1171. To find out which build you're using, go to the Apple Menu pull-down and select About This Mac, then click the More Info button. This opens the System Profiler utility. Click Software on the left and look under System Version. You'll see your build number in parentheses after the OS version.

Luckily, Apple addressed the problem in a software update on February 14. To get the update, which addresses this and a variety of other issues, open the Software Update System Preference and click the Check Now button. The update, labeled 10.4.5, is only a 6.4MB download for PowerPC Mac users, but a giant 40MB download for Intel Macs. The update doesn't fix every problem Intel Mac users have found, but it effectively cures the video-tearing issue.

Wireless woes
Several different wireless connection issues are plaguing users, but so far only one of the issues has a fix. If you aren't able to connect to your wireless network and you're using a Westell Versalink 327W router, then that's the problem. The Intel iMac doesn't seem to be compatible with it, so you'll need to switch to one from a different maker. An AirPort Express Base Station is pricey but will certainly do the trick. For more on this issue, this thread gets into the nitty-gritty details.

Other users have reported their wireless connections dropping out during long file transfers or oscillating between fast and slow throughput rates. With these issues, the solution isn't clear; discussion board members haven't yet discovered the source of the problem, and Apple hasn't released a fix. (Apple's official response is, "If a customer has any technical issues, they should contact AppleCare.") We tried several large downloads, including a 1.3GB file, and saw no problems with our review model of the iMac Core Duo, but that of course doesn't mean the issues don't exist. Until someone gets to the bottom of it, just know that some users have had wireless networking issues. If that feature is important to you, you'll want to follow the issue closely before you make a purchase.