An experience that may be useful to others:
Have had strange problems with my mid 2011 imac: freezing, functions in various apps like Indesign stopping working, half the keyboard ceasing to work, intermittent bluetooth mouse, browser issues and a few other oddities.... nothing I found on the net seemed to help but I did, from a downloaded app, find out my hard drive was on it's last legs. So good opportunity to upgrade to an SSD and very glad I did, super fast now but some issues remained, intermittently !
Then found out I could use twice the RAM I thought I could so started by testing the existing 16Gb using the apple RAM test on start up.... (option D after first chime on start up, with all peripherals disconnected, extended testing checked) and yes I found faults, but then I moved the RAM around to different slots to try to identify the offending module and retested. All the faults disappeared and the same happened with my macbook.
Conclusion is most of my problems were due to dirty contacts on the RAM.
Have had strange problems with my mid 2011 imac: freezing, functions in various apps like Indesign stopping working, half the keyboard ceasing to work, intermittent bluetooth mouse, browser issues and a few other oddities.... nothing I found on the net seemed to help but I did, from a downloaded app, find out my hard drive was on it's last legs. So good opportunity to upgrade to an SSD and very glad I did, super fast now but some issues remained, intermittently !
Then found out I could use twice the RAM I thought I could so started by testing the existing 16Gb using the apple RAM test on start up.... (option D after first chime on start up, with all peripherals disconnected, extended testing checked) and yes I found faults, but then I moved the RAM around to different slots to try to identify the offending module and retested. All the faults disappeared and the same happened with my macbook.
Conclusion is most of my problems were due to dirty contacts on the RAM.
