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PowerPC and Intel macOS Guide


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LowEndMac kinda has something like this, but it's not Intel friendly and I don't agree with everything they say. I'll make revisions based on input after this is done. I'll stick with stock machines for now, but I'll mention upgrades (for the purpose of installing later OS's) at the end. This will be for PPC models and Intel models no longer supported with OS updates. The general idea is to run the newest OS you can while also maximizing useability for the modern era.

You've got your shiny old Mac, and now you're trying to decide what you want to load on it. Here are some items to consider.


Pre-G3 Macs

This depends on your needs, specifically the needs of your software. If you've got a program requiring System 7, you should stick with that. Otherwise, I'd recommend 9.1 or 8.6, mainly because they both are rather PPC native.

G3 Macs

Varies greatly based on the hardware, but your VRAM is definitely something to consider. A Wallstreet probably has no business running Tiger (and it's not even officially supported - the cutoff is the presence of a FW port). The Pismo can run it okay (and I emphasize the okay). A Blue and White G3 with a Rage 128 should run Tiger well enough, as long as you've got the RAM needed (ideally 768MB or more).

Contrary to popular belief, Apple doesn't usually obsolete systems "just because", so if your Mac maxed out at 10.2 or 10.3, it's probably for a reason.
The main issue is Core Image, a beastly component of OS X, though Quartz Extreme is also a problem. Older GPU's just can't render this, which means choppy video performance, poor overall system performance, etc. This is an even bigger issue with Leopard, but we'll touch on that in the G4 section.

My general rule for G3 systems? 16MB VRAM or higher, you can handle Tiger well enough (iBooks should look at a faster hard drive). If you're 8MB or lower, I think you'll be happier if you stick with OS 9. You can consider 10.2 if you want, but 10.2's main purpose is running a more-compatible version of Classic, so…just run 9 on the metal.

No G3 should be running Leopard. Ever.

G4 Macs

Boy, what a spread we had of these! The G4 was around from 1999 to 2006, and ran at speeds from 350MHz to 1.67GHz, in single and dual processor configurations.

I'm going to start out with a brief discussion on Core Image, and why it's an issue for performance (especially with Leopard).

Core Image is used for cool effects, and to make things pretty.

Okay, it's for more than that, but I'm skipping a long technical dissertation. You can thank me later.

It was introduced in OS X Tiger, though it wasn't used as heavily until Leopard. It takes some GPU power to run it, which is why older models can't handle it well. Core Image, if not supported by the hardware, can run in software. Right now you're thinking "Well, that's great, right?" Not really. You see, when CI is run in software there's a 30% performance tax on the processor. That's a hefty bit of overhead, and while it's somewhat passable in Tiger because it's not used as much, your system is really going to take a hit with Leopard, which relies on it so much more heavily (OS gloss comes at a price).

Realizing this, Apple limits Leopard to install only on systems with a G4 running at 867MHz or higher. Not all of those systems have the right GPU, but they probably figured that at least gave enough CPU overhead for "okay" performance.

Here is a list of Core Image-capable cards: https://en.wikipedia.org/wiki/Core_Image#Supported_graphics_processors

As you can see, it does take some beefier GPU hardware, much of which was not available during the G3 and early G4 era.

Personally, I've run Leopard on the slowest machine supported, the 867Mhz 12" PowerBook G4, maxed out with 1.128GB of RAM. It's not horrendous, but it's definitely slower than Tiger. But, others have run Leopard on slower clocked Power Mac G4's, upgraded with a GPU that supports Core Image, and report much better results. I've also run it on the 1GHz 17" model, and performance was tolerable. It helps that that model held 2GB of RAM.

Another thing to consider is if you plan to run Classic Mode on your Mac. If you do, you'll need to run Tiger (or older). Leopard removed support for Classic in the OS.

Two biggest things for Leopard performance: Lots of RAM and a good, CI-capable GPU. If you don't have both, you're really not going to like your system. While Tiger runs well enough with 768MB, Leopard honestly needs 1.5GB or more.

I mentioned Quartz Extreme earlier; this was introduced in 10.2 and is a base component of the OS. The concept behind it is to offload the responsibilities for rendering visual components of the system from the CPU to the GPU. It has lower system requirements than Core Image. I can't find as comprehensive of a list, but here are some cards to get an idea of the minimum:  nVidia GeForce2 MX, GeForce3, GeForce4 MX, or GeForce4 Ti or any AGP-based ATi RADEON GPU. A minimum of 16MB VRAM is required installed in a 2X or better AGP slot.

Without QE support, again, your system is going to exhibit very choppy video performance.

I'll break it down by class below.

G4 Power Macs run Tiger swimmingly, of course, especially with a lot of RAM (and with as cheap as PC100/133/DDR is, you should max out your system anyway). You will get better performance with a video card that supports Core Image, however. No stock G4 card supported it until the FW800 revision of the Mirrored Drive Doors model, and even then only the top end card. With a GPU upgrade and full load of RAM, most Power Mac G4's should even handle Leopard well enough. If your model isn't officially supported you can use LeopardAssist to get it on there.

iMac G4's, the 1.0GHz models and up support 2GB of RAM, meaning they should be great in Tiger. Older models will handle it well enough, though with 1GB of RAM you'll see some limits. The 17" and 20" 1.25GHz models (distinguished by having USB 2.0) even support Core Image. Those models should likewise handle Leopard just fine, just max out the RAM.

PowerBooks, the first revision TiBooks used the exact same video system as the Pismo. As a result, neither Core Image nor Quartz Extreme is supported, meaning Tiger (and even Jaguar and Panther to some extent) will perform pretty poorly on the 400 and 500MHz models. It's not pretty, trust me. I feel that these are great 9.2 machines (and I run 9.2 on my 500MHz model).

The 550Mhz and up should do okay in Tiger. Not only did those models get better graphics, they also got the second-revision G4 processor, or G4e (7450), which is a much better performer than the older G4's. (In the Power Macs, the G4e is found in 667MHz or higher models). Max out the RAM to 1GB, and upgrade the hard drive from the original model, which is probably an anemic 4200RPM unit. Remember, ALL Titanium PowerBooks can run OS 9 natively, though the final revision 1GHz model needs a special version for that machine. With a 1GB RAM limit, no TiBook, regardless of "official support", should run Leopard.

The Aluminum PowerBooks (henceforth called AlBooks) start at 867Mhz and higher. There's a bit of a break in these models, however. The first two models, the 1GHz 17" and the 867MHz 12", are quite different from all other AlBooks; they're the only ones to have GPU's that don't natively support Core Image, and they're limited to USB 1.1.

The 12" 867MHz is also further hampered by a pitiful 256k L2 cache, and only having 128MB of RAM soldered to the board, meaning you can only have 1.128GB installed. All other 12" models have double the L2 cache, and 256MB soldered to the board, letting you go to 1.256GB.
These two will run Tiger well enough, especially with maxed out RAM and a faster hard drive. All other AlBook models will run Tiger very well.
Leopard...the 12" 867MHz is pokey. Not terrible, but pokey. I'd recommend sticking with Tiger. The 17" 1.0GHz is a little better thanks to extra RAM (and a 1MB L3 cache!). I'd say on that model, consider your needs carefully. All other G4 AlBooks, pick which one you want and run with it.

The need for Classic support will probably play the biggest role, IMO.

iBook G4's, stick with Tiger on all models except the final 2005 units, the 1.33GHz 12" and 1.42GHz 14". Those models upped the RAM capacity to 1.5GB and gained CI capable GPU's, so feel free to go to Leopard on them if you wish. Look into a hard drive upgrade.

The Mac Mini G4 will do best in Tiger. With a 1GB RAM limit and weaker GPU's, Leopard will seriously tax them. Consider upgrading from the 4200RPM hard drive as well.

As for the eMac, only the final 1.42GHz revision supports CI. Leopard can go on that if desired; all others, stick with Tiger.

G5 Macs

Good news! All Power Mac G5's will run Leopard, and all came with CI capable GPU's. Run the OS you want on those; as before, Classic support will probably be the big decider.

All but one iMac G5 model supports Core Image. The initial 17" 1.6GHz model had the option of an FX 5200 Ultra (which supports CI) or a GeForce4MX (which doesn't). If you've got the 4MX, you can probably still run Leopard well enough.

Overall, G5 Macs love Leopard.



Systems dropped with 10.6 and 10.7

All Intel Macs support Core Image, so that's not an issue.

My standard on where to go? Well, any Core Solo or Core Duo models cap out at 10.6, which is where I'd recommend they stay regardless. Snow Leopard is Leopard but much better, so run Snow Leopard.

Ultimately, it depends on the RAM. If your Intel Mac only has 2GB RAM as a maximum, stick with Snow Leopard for best performance. Lion really needs 4GB minimum for best performance, though 3GB is workable. (10.8+ needs 8GB+ ideally) Lion consumes 450-500MB of RAM all by itself, meaning you lose a quarter of your available 2GB RAM just from the system. Snow Leopard is much lighter at about 250MB.

Mac Pro 1,1? These things are limited, but they're great if you have a lot of PPC software you want to run under Rosetta. So 10.6 isn't a bad option.

MacBook Air 1,1? Lion works...but the system runs hotter (which causes that custom CPU to throttle pretty heavily). I personally prefer Snow Leopard on these, again mainly due to 2GB RAM.

X3100-equipped polycarbonate MacBooks will run Lion fine with enough RAM.

Systems dropped with macOS Sierra

Kind of a tossup here, really. Might as well stick with El Capitan.


Systems dropped with 10.6 and 10.7

Core Solo and Core Duo Macs will run 7 32-bit okay, but that OS is getting fairly dated at this point. The Mac Pro has the same issue of a 32-bit EFI, so you're stuck with a 32-bit install of Windows 7 at best, capped at 2GB RAM, and hampered in other ways. In many respects the Mac Pro 1,1 is the true orphan of the early Intel Macs.

Systems with X3100 graphics will run Windows 10 fairly well, actually. There may be some driver quirks and you'll need to trick the Boot Camp installer into bypassing the version check, but once everything is done, it'll work, at least for now.

Systems dropped with macOS Sierra

Really no reason not to run Windows on these. They should handle Windows 10 just fine (may want to look into an SSD upgrade and loading it up with a decent amount of RAM).


Beige Power Macs (pre-G3) can be upgraded with newer CPU's and made to run OS X, but you're also limited by old PCI slots, slow RAM, etc. It's probably best to not really bother with that these days, at least not for serious use (having fun is another matter, and somewhat out of the scope of this guide). Stick with the older Mac OS.

Beige G3's are limited to 10.2, with help you can get to 10.4, but again...slow system overall. The AIO isn't really practical as you'll be hacking a GPU into the system, and it's just a mess. Again, stick with the classic OS.

B&W G3's and PM G4's are fine to upgrade, though CPU upgrade cards are getting hard to find. More important is having a stronger, CI capable GPU and loading the machine with as much RAM as it can hold.

Intel upgrades; the Core Duo iMacs, and Core Duo/Solo Mac Minis can have a C2D installed with a little work, and you can then flash the firmware, enabling support for more RAM (3GB vs 2) and also allowing you to install Lion. Systems with a dedicated GPU should handle it fine; if you've got a GMA950, however, consider your use carefully. I find Lion graphical performance to be somewhat slow on a GMA950, to the point that I wouldn't really recommend installing Lion if you plan to use it regularly. Stick with Snow Leopard, though you can still do the hardware upgrades if you'd like.

I've personally done this upgrade on a Mini, taking a CD 1,1 model, installing 3GB of RAM, a 2.0GHz C2D, and flashing it with the 2,1 firmware, enabling me to then hack Lion on. For music server duty and HTPC uses, Lion handles well enough. For daily use it's not adequate.

The Mac Pro 1,1 is what I consider to be a 64-bit dirty system. Apple may have marketed it as a 64-bit workstation, but it's crippled with a 32-bit EFI, meaning it was abandoned after Lion. If you plan to hack more modern versions of OS X on, you'll need a GPU upgrade.
There are other 64-bit dirty Macs, but the Pro is really the only one with the hardware to competently run Mountain Lion and up.

Honestly, even if you're sticking with Lion I'd recommend a GPU upgrade; the GeForce 7300 is old and the X1900 is old and runs disgustingly hot. 10.7.5 supports the use of many older but popular nVidia PC GPU's (with caveats) or you can get a Mac upgrade.

Software breakdown

Why no love for the earlier versions of OS X? 10.0 and 10.1 might as well be a beta, so unless you want to run them for the historical value, they're rather pointless.

Jaguar has some benefits; better Classic support and more legacy compatible AppleTalk/EtherTalk support. It doesn't have a truly modern browser anymore, however, so keep that in mind. Classilla works in early OS X but it is limited at the moment.

Panther is more stable, but OS X really opened up with Tiger. That's the reason there's a bit of a "If not Tiger (or Leopard), then OS 9" element to this guide; it's in the interest of maximum usability and software compatibility. If you have a program that requires 10.2 or 10.3 (and some exist), or you want to use 10.2 on a bridge Mac, then you'll end up needing one of those, of course. Just don't expect to do very much with it.

10.4 or 10.5?

What do you want to do with it?

10.4 allows you to still run Classic, it has the older UI, it's lighter on older hardware, etc. It still has a (rudimentary) form of Spotlight, and it runs TenFourFox (hence the name), so you have modernish web browser support. If you're after productivity on older hardware, it may be worth considering. One other factor is that Tiger is available on CD if you can find someone selling it, while Leopard is DVD only. Tiger is also generally cheaper on the used market.

10.5 adds Time Machine, support for iTunes In The Cloud (though with no Apple Music support this is something of a moot point now), performance enhancements, faster Spotlight, a newer UI which mostly carried forward through 10.9, later application support (though many people also dropped 10.5 support when they dropped 10.4), and drops Classic and pretty much all AppleTalk support. It's also more resource hungry. Leopard is a Universal installer so it will run on Intel machines (though I don't know why you wouldn't go to Snow Leopard or better), but the install discs tend to get expensive at times; watch the market carefully.


Unless your system is running El Capitan (prior to the release of macOS Sierra), none of the machines in this guide are receiving security patches. Once Sierra is released, El Capitan will no longer have a guarantee of security. As such, there are steps you should take to harden your system.

1. Flash must go. Seriously, Flash might be one of the worst programs ever conceived, and it's a security nightmare regardless of platform. Don't try to hack new versions, don't do 'fixes', just remove it entirely. Very little still relies on it apart from ads and content that is generally worthless at this point. 

2. Java should be removed from 10.7 and older as well.
3. 10.4 and up are subject to Shellshock; for 10.4-10.6, run this Bash update: http://tenfourfox.blogspot.co.uk/2014/09/bashing-bash-one-more-time-updated.html?showComment=1411776746795

10.7+ were updated by Apple.

4. Be careful what you download. This goes for any platform, but especially here. 

5. All PowerPC Macs were dropped by browser makers years ago. Firefox is still supporting 10.6-10.8 through the end of 2016. TenFourFox is an option for 10.4-10.6 for a little while longer, but I'd invite you to consider the security implications of web browsing on machines that, in some cases, have gone without patches for seven years or more.  

6. Strongly consider turning IPv6 off. It's on by default in 10.3 and up.

Really, at this point, older Macs probably shouldn't be on the greater internet anyway. If you want to keep it only on your LAN, I'd still recommend hardening it.

OS 9 and older, your biggest risk is downloading some old Mac virus with a file or something. Just be smart, but for the most part there's really very little risk for those systems.

This is hardly an all-inclusive list of security issues, and it may be expanded in the future.

Hopefully this guide was of some use! As always, I'm open to opinions and suggestions, and feel free to post personal experiences below.

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I think this is a good guide, and I'd generally agree with your pitch that it's 10.4 and up or OS 9. I used 10.3 on and off for a few years on my 466 Mhz iBook, and one of the things I noticed was that software compatibility with 10.3 pales in comparison to 10.4. There's a lot of useful software for 10.4 that simply will not run on 10.3 (I'm thinking about Bean, TenFourFox, etc.). Anecdotally, I've also found that 10.4 is thoroughly usable for writing, email, and some basic web browsing (mostly using my University's online print service) on my 400 MHz Pismo with the RAM maxed-out. I've turned off Spotlight and Dashboard, and that seems to help a little. If you're really looking for better performance, ShadowKiller works well for that at the expense of making the UI look absolutely awful. I don't use it too much because of the UI thing, and caveats about it being a haxie abound, but it does seem to work. 

Likewise, I'd also add that unless you really need the features of 10.7 or a piece of software that will only run on 10.7, my experience is that you should probably be running 10.6. It's very stable and reliable, and 10.7 introduces a lot of bloaty new features that weren't really made useful until 10.9 at the earliest. Your millage may vary, of course.

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