Speed Up Mac OS Boot – Disable RAM Tests

Mac OS 9.0 Loading

At the very start of the Macintosh boot process, after the startup chime, a Mac will undertake a RAM test to ensure that the machine’s RAM is fully operational before attempting to load the OS into it. This sounds like a great idea in principle, and in the early days of Macintosh, it was probably a very good idea in fact as well.

However, time moved on, and the amount of RAM being deployed in new Macintoshes increased by leaps and bounds. The RAM test that once took a small number of seconds started to stretch out into a large number of seconds, introducing a very perceptible and somewhat heart stopping delay into the boot process.

My Power Macintosh 7300/200 has 640MB of RAM, and the testing of this complement of memory takes between 45 seconds and a minute. During this time, there is no obvious outward sign that anything is happening at all. You hear the startup chime, and then to all appearances the machine just sits there, doing nothing. About 45 seconds later it springs to life and Mac OS starts to load.

The situation is very similar on my Quadra 840AV. That machine has only 128 MB of RAM deployed (the maximum amount the 840AV will support), but since the CPU is slower (40 MHz 68040) the net result is about the same. One experiences the startup chime, then 45s to 60s of apparent nothingness, and then the boot process.

Simply stated, I got tired of waiting for the RAM tests to complete as a necessary precursor to booting and decided to disable them. Vaguely remembering that I could disable the tests via a setting in the Memory control panel, I went there looking for the setting. Quite to my surprise, it wasn’t there! Here is what you see on Mac OS 9.1 when you select the Memory control panel.

Orig Mem Ctl Panel

I hunted through all the other likely control panels, assuming that I had just remembered things incorrectly, or that perhaps the setting had been moved to a different control panel in Mac OS 9, but I simply could not find it anywhere. A search of the web ensued, and ultimately I unearthed the answer. It is the Memory control panel, but the Enable/Disable for the RAM tests is hidden! I am sure that his was done to protect users from themselves, but it also “protects” advanced users from accomplishing a useful task.

Here is what I discovered. To unhide the RAM test enable/disable option, hold down the CMD+OPT keys while selecting the Memory control panel. When selected in this way, a new option magically shows up at the bottom of the panel, which now looks like this:

Extended Mem Ctl Panel

Select “Off” for the Startup Memory Tests, and close the panel. The next time you restart your Mac, you will observe that the boot process begins more or less immediately, resulting in a much shorter overall time from power on to fully booted. You’re welcome! 🙂

I wish to extend a big thank you to “Giant Mike”, at whose web page (www.giantmike.com) I found the magical keystrokes to show the hidden option in the Memory control panel.


In fact, the giantmike site has a full page of tips for speeding up your vintage Mac. You will find them at the below URL:


Great job Mike, and thanks for the tips! A particularly useful one, after the one about disabling the RAM tests, is the tip to rebuild your desktop on a regular basis. Do this routinely and you will keep your vintage Mac humming at optimum speed. Thanks again Mike.

Zoom Zoom! (…with apologies to Mazda! 🙂 )

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