Leopard: Speed, Stability and CompatibilityEven though this is a beta version of Leopard, I've been using it pretty fairly regularly for the past few days and I do have a brief report on how usable it is and I've split it up into how fast, how stable and how compatible it is.
I'm afraid to say that I have had four Kernel Panics (grey screen curtains down and asks you to restart by holding down the power button) since last Thursday. And, even more interestingly, they seem to happen at the most random times when I am doing nearly nothing with the computer. The last one happened after I began using the machine having left it idle for nearly 12 hours and opened Safari; midway through the second bounce, the machine panicked.
However, apart from the kernel panics which I have to deal with every now and then, application-level stability seems to be high. Apart from two iChat crashes, Safari crashing on particular web pages, and Mail and Time Machine just being immature pieces of software, I really haven't faced too many issues of weird app behaviours in Leopard. But, as long as the kernel panics exist, there's always a thought at the edge of my mind that this machine can go down at ay time and without a warning; so, that makes me uncomfortable while using it.
I measured the start up times for both Leopard and Tiger installed on the same day on this same computer from the appearance of the grey Apple logo to the appearance of the login window and the results are: 23 seconds for Tiger (10.4.10) and 32 seconds for Leopard (9A466). So yes, the results for Leopard are impressive considering that it is still a beta and are considerably better than all the previous betas of Leopard I've tried. The login times for Tiger and Leopard have about the same margin of difference - Leopard is slightly slower.
But what about the feel of the system with all the new effects, translucency and reflectivity? I feel that, on today's machines, users probably won't feel any difference in performance with all the extra effects in Leopard. However, my Mac represents the lower end of the spectrum as far as Macs go (notebook, single G4, 64MB graphics) and running the Leopard beta on this machine has told me that Apple's minimum requirement of 800MHz is actually very generous. Unlike Vista, Mac OS X does not scale back any cool graphics on slower computers (it will scale back some cool GPU-dependent animations though). And there are a lot of new effects in Leopard (which will only increase in number by the time it ships); with the addition of Core Animation, anything that can possibly be animated has been animated in Leopard. Any kind of movement, growing or shrinking, etc. – it's all fluid and animated. And yeah, it does bog down my Mac. Resizing windows, launching applications, etc. is noticeably slower in Leopard. Also, although my Mac deals fine with small stacks, the larger stacks in the Dock (such as the one for my Applications folder) are not exactly as fluid as the demo you saw at apple.com. So, in short: I would recommend Leopard only for the last generation of G4's for decent performance and nothing less than a G5 for really good performance, because, even though this is beta, performance isn't likely to take any huge leaps between now and October.
Dashboard: Dashboard deserves a special note in Leopard because, even from the first Beta, it has been remarkably fast in Leopard as compared to Tiger. The cause for this seems to be that all the widgets are launched under a single thread as opposed to each one being spun off in its own thread by the Dock. This way, the system doesn't need to create a separate stack for each widget and there's no context-switching involved between widgets. It's like Dashboard on afterburners. The initial launch of Dashboard after a fresh boot is now much more bearable and this is one feature that I would love to have in Tiger now. It's probably the only thing that's actually faster in Leopard.
Spotlight and Time Machine: Sure, I mentioned in the previous Leopard post that Spotlight had caught up to Vista's Live Desktop search in terms of speed, but what about indexing? As you may know, on a fresh install, Tiger and Leopard both have to index your hard drives. Unfortunately, although Tiger did this unobtrusively, Leopard was barely usable while Spotlight was indexing or Time Machine was performing backups on my Mac. Also, from my testing, it seems that Leopard's and Tiger's Spotlight indices might not be compatible, because, after doing a full index, when I booted up into Tiger, it started doing its indexing and once that was finished and I booted back into Leopard, it began reindexing. So, I've told Tiger not to index the Leopard drive and vice-versa.
There are only a couple of pieces of software that I have tested which just haven't worked, such as Google Earth and OnyX - the former crashes on startup and the latter shows a message telling me my Mac OS X version is inappropriate. Other than that, I have been using a lot of run-of-the-mill Tiger software (none of it is system-level software) and it has been working fine. I'd hazard a guess that anything that attaches a daemon, a kernel extension or something of that sort is more likely to run into compatibility issues. I also haven't tried Unsanity's Application Enhancer-based applications but I'd be willing to bet a decent sum that they're incompatible with Leopard. In general, anything that has a drag-and-drop installation has a very high chance of running just fine in Leopard but anything that needs to use an Installer probably also needs to be updated for Leopard. The only software I miss the most while running Leopard is Apple's Remote Desktop which really is the killer app for me - I just can't use Chicken of the VNC as a permanent replacement and unfortunately, Apple won't come out with a new ARD until Leopard has shipped. Sigh.