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Leopard II: iMac video issues revealed

updated 04:10 pm EDT, Mon October 29, 2007

Leopard 2nd Take

When we first tested Leopard, initial impressions of the new OS were very favorable, and many of these initial observations hold over after days of extended use. The OS continues to not just run quickly but also upgrades the performance of a few previously sluggish components, especially Spotlight. We've discovered a few pleasant upsides to Leopard since then; however, we've also found a few potential showstopping bugs that may have early adopters think twice.

The more we use Leopard, the more it becomes apparent that the most significant upgrades to Mac OS X may actually be its Internet-based features rather than Time Machine or even the reworked Finder. iChat is especially beneficial to anyone who regularly speaks with friends online using AIM (or, in some cases, Jabber); the organization of buddy lists and multiple chats is just as useful to any user as presentations and screen sharing are for business. Safari's on-page search tools and Dashboard's new widgets (including WebClip-generated widgets) are also handy for anyone finding a buried word in a large article or checking on movie showtimes.

Spaces may also be a far more useful addition than expected, particularly for users with small (or crowded) displays on notebooks; it eliminates the need to continually switch to and shuffle app windows and may let some MacBook users put off buying an extra screen if their workflow doesn't require too many immediately visible (but still important) programs.

However, we've encountered significant compatibility issues that might preclude some users from enjoying Leopard right away -- if at all.

Most of these appear to have their roots in the rough drivers for AMD's ATI Radeon HD video card series, which Apple has acknowledged is causing freezing issues for the newer iMacs that use it. Upgrading to Leopard doesn't resolve this issue, which will reportedly be fixed in the near future for both the new and old operating systems. Until then, however, backing up work may be a routine for iMac owners as the freezes often happen without warning.

In fact, the OS may also have added its own share of display-related issues that are typically absent in Tiger. While intermittent, we've seen brief instances of pixel artifacts around Dock icons and one instance of white "streaks" flying across the screen, which previously only appeared in a Boot Camp install of Windows.

More disconcerting are outright shutdowns of the video system in certain conditions, particularly when Mac OS X invokes a full-screen mode. We've seen instances of Front Row, Time Machine, and the third-party game Warcraft III all randomly turning the screen completely black; when this happens, the only choice is to restart the system entirely, even though background sounds reveal the OS itself is working properly behind the scenes. These issues are borderline unacceptable, particularly on a new iMac which is supposed to represent the best Leopard (and Apple as a whole) has to offer.

Still, if Apple can resolve these problems and it turns out that the issue hasn't spread to other Macs, the OS should still be a clear step forward for most users. As much as these features limit using Leopard as intended, it would be hard to step back to Tiger's comparatively basic feature set.

by MacNN Staff




  1. DaveHuston

    Joined: Dec 1969


    20-inch or 24-inch?

    I've seen reports of this occurring on the 24-inch iMac, but I have yet to hear of this happening to the 20-inch models.

  1. sleadley

    Joined: Dec 1969


    Leopard problems

    There are some things that have not been mentioned regarding Leopard and they see the oS going backwards in some area. Apple have removed the ability to send an SMS from Addressbook via Bluetooth. Many many people found this very useful, including me. In Mail, I can no longer drag Mboxes to the desktop. I used this to move my junk email so that I could report it with SpamX. This no longer works. I would prefer that any backup system created a bootable volume which Time machine does not do. What happens if the HD crashes, you then have to reinstall the OS before using Time Machine to restore your backup. If I use Superduper I can boot instantly back to where I was when I did my last backup using the backup disk and be working within a very short period of time. Overall, Time machine seems a little light on options but still might be good for most people. my 2c Simon L.

  1. jameshays

    Joined: Dec 1969


    re: leopard problems

    You don't have to resinstall the OS first, you have to boot off the CD and then choose to restore from backup. No big deal.

  1. sampac

    Joined: Dec 1969


    iMac Freeze

    Thank you for posting this. My iMac still has a lot of freezing issues and applecare claims still not to know anything about it. I hope a fix comes out soon or i will have to get the graphics card replaced. Digg this please

  1. Mixotic

    Joined: Dec 1969


    Time Machine backup boots

    If it's true that you can;t boot from a Time Machine backup, this is a sorry oversight on Apple's part. If your drive dies on a laptop, you won't be able to restore until you purchase and install a replacement drive. That's pretty limiting.

    Do yourself a favor. Trash the Time Machine icon and download Mike Bombich's fantastic Carbon Copy Cloner. Then make a donation!

  1. panjandrum

    Joined: Dec 1969


    ATI card overheating?

    Those video artifact issues sound a *lot* like the video chipset is overheating. Apple's had a lot of problems with overheating recently (including the first version of the Radeon X1900 XT they put in the MacPros), so it wouldn't surprise me at all if this turns out to be the issue here also.

  1. G4_Kessel

    Joined: Dec 1969


    Not just iMacs

    Mac Pros with the X1900 are having a lot of graphics problems too! See for yourself:

  1. Xiaopangzi

    Joined: Dec 1969


    Logic board problems?

    I used the default upgrade option on my wife's iMac G5 instead of the safer archive + install custom option that I used on my MacBook Pro. Soon, artifacts appeared in interesting places on her screen, and then restarts were plagued by white streaks running across the screen, even when starting from the Leopard installation disc, and then finally, all video was completely scrambled seconds after any attempted force restart from the internal disk or the Leopard DVD.

    I recognize these as clearly logic-board-related problems, having gone through 8 logic boards in my iBook G3/4(??) and one in this same iMac a few months after its purchase.

    We've already taken the iMac in for repairs according to the extended warranty (, but I'm hoping that Apple doesn't start to confuse this clear problem that arose immediately after a Leopard installation with other iMac-related video problems that are in fact related to Leopard, as it will only delay the needed logic board replacement.

    I sure hope that Leopard isn't too demanding on the G5 chip, causing logic board melt-downs that lead Apple to request that such owners downgrade. The timing of this failure is really suspicious and too coincidental, appearing right after an upgrade to Leopard.

  1. testudo

    Joined: Dec 1969


    Re: leopard problems

    You don't have to resinstall the OS first, you have to boot off the CD and then choose to restore from backup. No big deal.

    And if you just need to get something done? A bootable drive allows you to continue working. A non-bootable drive forces you off to another computer (if you can find one), dig up your files, and then try to launch them (assuming the other mac has the apps you need installed).

    To expand on mixotic, forget the 'laptop' part. Most macs don't even have the drive as a user-replacable part (not without lots of effort), so you're taking the whole computer in just to swap out the drive.

  1. Roehlstation

    Joined: Dec 1969


    Time Machine

    Time machine was never intended to be used in such a way. It creates incremental backups of files which is useful in a completely different way (imagine being able to go back to any stage in a project) as an architect I love Time Machine; model files that I work on for months are very protected. In order to get incremental backups in the past I had to pay a lot of cash to get that. Carbon Copy Cloner or Super Duper rocks for the application you would use that for, I use it constantly to get disk images.

    As far as hard drive replacement in laptops, the MacBook is totally user replacable, and I dearly hope the MacBook Pro will be in next revision (although they are a lot easier to get too than they were in the G4s.) But I'm a Mac Pro user now so accessing hard disks is about as easy as it gets, For Leopard I slapped in another drive and installed there, used data migration assistant to copy all my settings and apps from the old drive, now I'm able to dual boot and test all my apps without losing productivity, I can simply boot back to Tiger after I've made a list of what Apps I have to wait for updates for. Windows has never been that easy.

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