Setting Up a Power Mac 6100

Five years ago, my employer was spending about $3,600 for a Power Mac 6100/66 with 16 MB of memory (so much!) and a 230-500 MB hard drive. And Apple’s extended keyboard, which was a separate item back then. And an Apple 14″ color monitor.

Power Macintosh 6100To save money, our dealer pulled the 2x CD-ROM drives and gave us a credit of about $200 per system. When buying two dozen computers, that really adds up.

Five years later, we’re still using all of them. Just last week I move our receptionist from an accelerated Mac IIci to a Power Mac 6100/66. She’s thrilled with the speed, as are those who fill in when she’s on break or has a day off. The 6100 is our basic workhorse Mac as well as the one we have the most of.

At Home

Umax SuperMac J700I’m currently using a SuperMac J700 with a 250 MHz G3 card. My oldest son has a SuperMac S900, which runs a 200 MHz 604e. Below that, I have a Centris 660av, Quadra 650, and Quadra 630, which handle my ISDN internet connection, web and email for, and my email lists, respectively. (For US$999, I could replace them all with a 350 MHz iMac – but the budget doesn’t allow that right now.)

Next down the list is my second son’s Color Classic with a 25 MHz 68040 accelerator, followed by my old Centris 610, my IIfx, and my wife’s PowerBook 150. Below this, we have a couple IIsis, an SE/30, a IIcx, a Mac II, an LC, an LC II, a Portable, an SE, and a Plus. (I take my low end Mac computing very seriously.)

The Deal

So when Small Dog Electronics, a sponsor of several Low End Mac email lists, announced they were taking in a quantity of Power Mac 6100s at $199, they got my interest. These were refurbished computers with 8 MB of memory, a 230 MB hard drive, a 2x CD-ROM, an extended keyboard, and a mouse.

These would be a big step up for my sons, especially since some of the older Macs didn’t want to work with ethernet (notably the Color Classic with the Sonnet Presto card). I’ve been sharing my Mac with most of the family for web and email, and that can be frustrating for all involved.

The three “new” 6100s arrived this week, so I spent the weekend setting them up for the three youngest boys. I bumped memory, since you can’t run any version of OS 8 or later on an 8 MB computer. I had extra AAUI adapters, so attaching them to my ethernet hub will be easy. And I recently took advantage of a $50 deal for Mac OS 8.5.1 plus Norton 4.0 and a couple games.

The systems came with System 7.5.3 installed, which is fine. Mac OS 8.6 uses a lot more memory and drive space, but if you can afford to boost the computer’s memory, I think it’s worth it for the improved Open Transport networking, far faster virtual memory (VM), and Sherlock.

The first step was to stack the three computers, setting them sideways so it’s easy to get to the connectors on the back. Each one in turn was connected to keyboard, mouse, monitor, power, and a Zip drive. Then boot from the 8.5.1 CD, format the hard drive as HFS+, and spend about 20 minutes installing Mac OS 8.5.1.

This occupied about 150 MB on the 230 MB drives. Booting from the hard drive bumped that to about 190 MB in use, since the OS defaults to turning virtual memory on.

This was followed by running the Mac OS 8.6 updater from the Zip drive. I learned that with virtual memory on, there wasn’t quite enough drive space to run the updater, so I turned off VM, rebooted, and ran the installer again.

In the end, we had three almost identical computers with the same amount of memory and drive space.

But they weren’t quite the same. One was a Power Mac 6100/60 – which is what Small Dog listed as the model for sale. Another was a 6100/66, and the third was a 6100/66 with a 256 KB level 2 (L2) cache. By luck, the boys had picked the Power Macs before setup, and the youngest had the slowest machine, with my second0-oldest son getting the fastest.

I ran them through their paces with Speedometer 3, Speedometer 4, and MacBench 5. I made some interesting discoveries, which are in my benchmark report, but here are a few of the interesting findings:

  • With these benchmarks, these systems, and this OS, it made no significant difference whether virtual memory was on or off. (Of course, turning it on greatly reduced the 80 MB or so of free space on the hard drive, so we’re leaving it off for now.)
  • The 256 KB L2 cache really boosted graphics performance. This is because the 6100 uses system memory, not VRAM, for video. Since the entire amount of memory used for a 640 x 480 8-bit display fits within the 256 KB cache, it boosted performance by about 25%.
  • The 6100/60 scores 100 on the MacBench 5 CPU test – exactly one-tenth the speed of a 300 MHz Beige Power Mac G3 (beige). That’s a significant difference. But it’s also 2-4 times the performance of the accelerated Color Classic, so it’s a big step forward from what the kids had been using.

The other interesting discovery: Mac OS 8.6 eats up about 18 MB of memory, but with virtual memory (VM) enabled, that drops by about 7.5 MB. If there were more free space on the hard drives, I’d leave VM on – but that will have to wait until we can find some bargain hard drives in the 1 GB or larger range.


Was it worth it? Considering we already had extra monitors, pulled memory, and AAUI ethernet adapters, yes. If not for that, the cost would really add up:

  • $100 or so for a VGA monitor
  • $10 for a Mac-to-VGA adapter
  • $40 for an AAUI ethernet adapter
  • $20 or more for two 8 MB 72-pin SIMMs, at least $50 per pair for 16 MB SIMMs, or $110+ for a set of 32 MB SIMMs

You’ll really want 40 MB of physical memory in a 6100 with OS 8.0 or later. Since we aren’t using VM due to limited drive size, and OS 8.6 uses about 18 MB, a system with 24 MB of memory (built-in 8 MB plus two 8 MB SIMMs) only ends up wiyh 6 MB free – not enough to run Netscape or Internet Explorer. Jumping to 40 MB (using two 16 MB SIMMs) gives you 21 MB of free memory for browsers, games, and more.

But you have to weigh all of it against the $999 350 MHz iMac. It has a huge hard drive, 64 MB of memory, a very fast CD-ROM (especially compared with the 2x drive in the 6100), a multiscan 15″ screen, 10Base-T ethernet, and a blazingly fast 350 MHz G3 processor.

For about $400, you can have a very nice, very usable five-year-old Mac system that can even run Mac OS 9. For a bit more than one entry-level iMac costs, you can have three 6100 systems – and eliminate any fighting over whose turn it is.

If you already have some Mac equipment, the older Macs become an even better deal. I’ve managed to set up three systems for about $600, although I may need to pick up another monitor. It’s not state of the art, but it’s very usable.

Considering these were the core of $3,600 systems five years ago, I think they’re an incredible value. And it’ll be easy and inexpensive to drop in a larger SCSI hard drive when the kids can afford them. (Two of the boys are investing paper route money in these machines.)

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