Getting the Most from a Power Macintosh 6100

Getting the Most from a Power Macintosh 6100

I’ve been doing a huge amount of benchmarking over the last week and have been using my 6100/66 as the comparison machine. I though I’d post a couple of comments on how to get good performance while it is on my mind.

Processor Upgrades

If you are able to find one at a reasonable price, a G3 upgrade, for example from Sonnet or Newer, is the biggest performance boost you can get for a 6100. The performance boost is huge. A 266MHz G3 Sonnet in my 6100 increases Norton System Info CPU benchmark scores by about 560% for my 66MHz 6100.

Note when you fit a G3, you usually have to remove the L2 Cache SIMM from your logic board. Mine won’t even boot if I forget.

An advantage of many of these G3 upgrades is that they also act as a PDS raiser card, allowing you to fit an AV card. This gives you the ability to drive higher resolution monitors and/or more colours, as well as dual screen.

A Level 2 Cache

If you can’t get a G3 processor, make sure you have an L2 Cache fitted. This allegedly gives a performance improvement of 20%. I don’t have my benchmark scores on hand at the moment, but feel like 15% on CPU is more realistic. It also significantly improves built in video performance. Very worthwhile.

Use Built-In Graphics

Even if you have an AV card fitted, while the more conventional connector is nicer, and the 2MB of VRAM is good for higher resolutions and bit depths, the built-in video port gives faster video performance. If you have an AV card fitted and aren’t using it, it still appears as connected, so to save a small amount of CPU usage, set it to a low resolution and low bit depth. I think it supports Black and White.

To use the built-in video, you’ll likely need a HDI-45 to Apple RGB (15 pin DSub – not to be confused with VGA) adapter, and then perhaps an Apple RGB to VGA adapter as well. Don’t pay too much for one, certain sellers on eBay have been trying to produce artificial scarcity and drive up prices. They’re pretty common really.

Software Tweaks

If you’re planning on running older games on your 6100, even if not, you must install SpeedDoubler 8. It gives approximately a 500% improvement in emulated 68k benchmarks on my machine.

Additionally, consider installing MathLibMoto for a small improvement in floating point performance in some situations.

If your software is looking for a 68k FPU (a 68882), try installing PowerFPU.

System Software

I recommend running Mac OS 7.6.1 if you have 24MB of RAM, perhaps Mac OS 8.1 if you have 40MB or more and want HFS+ disks.

Remember that dual booting, or even more, is pretty trivial on a vintage Mac. I usually install three OSes on my machines, if I have room, by partitioning the disk. I’ll install an early supported OS, a middle era OS and late OS. For the 6100 this might be 7.5.3, 8.1 and 8.6, or perhaps 7.1.2, 7.6.1 and 9.1, or whatever.

RAM

I recommend you have between 24 and 72MB of RAM. The 6100 will accept up to 264MB of 72pin FPM RAM, but more than 72MB isn’t really needed unless you’re capturing video or audio, or using a big RAM disk. Note if you fit 264MB, the screen will stay blank for about 37 seconds while your computer does the memory test at power on.

There is 8MB of RAM soldered to the logic board, and two SIMM slots which must be upgraded in matched pairs.

A Fast Hard Disk

A modern SD card to SCSI adapter is likely your best option as most old spinning SCSI disks are close to failure and expensive. Avoid the original BlueSCSI as they have a high failure rate and are slower. Newer options include the MacSD, ZuluSCI, GBSCSI2 and BlueSCSI.

New Battery

Be warned that old batteries leak and destroy old Macs, so make sure you aren’t running a battery that is more than about 10 years old. Don’t leave the regular half length AA batteries in when the computer is stored.

Ideally, I recommend getting a coin cell battery adapter as they are less likely to leak.

Capacitors

Keep an eye on the electrolytic capacitors on your logic board. If you notice the solder on the pads loses its shine, you probably should recap the board. You shouldn’t need to do caps other than the electrolytic “tin cans”. The power supply might need doing too. I haven’t needed to recap my 6100 yet, but I keep a careful watch and am willing to do it myself. I probably should have done the logic board already.

While many Macs will run without a battery, the Power Macintosh 6100 needs the battery to properly power on. With a missing or flat battery, you won’t usually see a video output, although you can do a trick where after powering it on, you quickly turn it off and back on again. This isn’t advisable generally but can be useful to verify a machine works.

Software

Less relevant to the performance of your 6100, but the following is some suggested software for your Power Macintosh 6100…

Productivity and Creative

  • Photoshop 4
  • Illustrator 5.5
  • Painter 3
  • Propellerhead RB-338
  • ClarisWorks 4
  • HyperCard 2.3
  • Word 5.0a
  • Infini-D 3

Utilities

  • Speed Doubler 8
  • AfterDark 4
  • The Grouch

Games

  • Marathon Infinity
  • SimCity 2000
  • Settlers II
  • Civilization II
  • Oxyd
  • Myst
  • Lemmings
  • Escape Velocity
  • Glider 4

For Kids

  • KidPix
  • Thinking Things Collection 2
  • Just Grandma and Me

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