Tip of the Week

In preparation for the roll-out of its OS X operating system, Apple Computer Inc. put out a “firmware” upgrade last month, designed to tinker with the computer’s hardware settings.

But many Mac users who applied the update found that their computers no longer could see all of the RAM their systems had on board. Apple said the firmware does disable third-party memory that doesn’t meet the company’s specifications, arguing that out-of-spec memory is largely responsible for system crashes.

Some RAM manufacturers have offered to replace RAM that no longer works. Check to see whether yours does.

If you haven’t installed the firmware upgrade yet, you can see whether all your RAM will work using a utility called DIMMFirstAid, which also will try to resurrect your disabled RAM if you’ve already been hosed. The link is https://www.versiontracker.com/moreinfo.fcgi?id=10415.