These days, Apple's excellent OS X in its various versions is the operating system to have. Its power, elegance, and simplicity are unmatched by any other OS out there. But older Macs often have problems running OS X well enough to take advantage of its many excellent features. This is a brief overview of my experience with the best older, lower-cost Mac desktops and laptops that are suitable to run this awesome OS.

Let's establish some ground rules here: The best version of Mac OS X to run on older hardware and still experience what X will do for you is OS 10.3.9 Panther, which is available at good prices right here on eBay. OS X 10.4 Tiger is a great system, but requires twice the RAM that Panther wants. OS 10.2 Jaguar wants the same RAM amount that Panther does, but is slightly slower-running at best.

So, let's look at desktops. For all practical purposes, we begin at the very low end with the excellent Power Mac G3 blue & white. These attractive desktops feature ease of upgrade (one side opens up for access to just about everything inside) and, despite their age, a lot of computing power even today.

These G3s are different than the older beige G3s which are good machines, but require some work with video RAM and other components/functions before they can really handle OS X the way it needs. They can be had on eBay for less than $100.

First thing for purchasing one of these machines is to be sure to get one that has a "Revision 2" motherboard, which features support for multiple hard drives and resolves an issue with video function that plagued earlier Rev. 1 versions. If you should happen to settle on a 450 MHz G3 b&w, it has the Rev. 2 motherboard, so no problem. Earlier 350s and 400s, find out before purchasing.

Also, for the sake of speed in running X, get at least a 5400 rpm and preferably a 7200 rpm hard drive, minimum 20 gig capacity. More is better.

Next, and here is a principle that applies to any machine you run OS X on: You MUST have a lot of RAM. A good G3 with a gigabyte of RAM will run Panther faster and better than a good G4 with only 128 megabytes. This is because X uses RAM dynamically with all programs, and will swap out hard disk space to use as memory when RAM runs out. Hard disks run 'way slower than RAM, so there you have it.

For Panther, 256 megs of RAM is an absolute practical minimum. Any more than that is highly recommended, and pure gravy for your computing experience. I have 768 megs, and Panther is a speedy cat with that much.

Slot-loading iMacs, with their 100 MHz system bus and easy RAM upgrading, are also good candidates for X, but I would not install a 7200 RPM hard drive in one of them as it raises internal temperatures too high. 5400 RPM is the choice here, and will run OS X just fine.

The b&w G3s are to be considered the practical low-end for OS X, so what's next up from there? The great G4 line, especially the early dual-processor 400, 450, and 500 MHz models. The G4 has significantly more raw computing power than the G3, and features the "Altivec" engine, which speeds up certain high-capacity software programs--like the ones in OS X. Compare with the G3s, and while the G3s won't be left in the dust, they will come in a definite second.

The dual-processor models deserve special mention here, because OS X is designed to make fuller use of the dual processors than previous Mac OS versions, and I can testify that the difference is major, even awesome in use. The dual 400, 450, and 500 MHz versions are the low-cost champs here, can be had inexpensively, and are straight-on reliable with the same ease of upgradability of the b&w G3s.

From here, we go up into the "Quicksilver" G4 line and eventually right out of the low-cost range, but if you can manage the expense, you'll get a great machine for OS X.

So what about laptops? They tend to run a little costlier than the desktops, so I'll just cover the low-end OS X models and let you go from there to as expensive as you can afford.

Remember the clamshell iBooks? Well, all of them are capable of working with OS X, but a couple of models are standouts. These would be the 366 and 466 Mhz clamshells with FireWire inputs. These can take up to 576 megs of RAM (a good idea for X), memory installation is easy, and 10-gig 4200 RPM hard drives in these are adequate for OS X operation. They are rugged and reliable, and are gaining in collectibility due to their unique design.

Among the PowerBook G3s, the standout and one which I recommend is the "Pismo" model. This excellent laptop features either a 400 MHz or 500 MHz G3 processor, a RAM capacity of 1 gigabyte (excellent for OS X), a fast 100 MHz system bus, 10 & 13 gigabyte hard drives standard, two USB & two FireWire ports, and a nice 14.1" color screen, as well as a DVD-ROM drive for watching movies. The Pismo can also accept TWO batteries for up to ten hours of uninterrupted portable operation.

And there you have it! These models are the "cream of the crop" among Apple's older OS X capable machines. There are, of course, others in this range that will run OS X, but these are the ones to really look for, the ones that, in my experience and opinion, will give you the best OS X bang for the buck, and get you into this terrific operating system for very little money. Of course, eBay is a great place to score a good bargain.

Happy hunting, and best of luck!