Q: imac (late 09) memory upgrade

Please watch http://eshop.macsales.com/installvideos/imac_late_2009_mem_m/ for instructions on how to correctly install the RAM.

Exactly what RAM did you buy? Please be as specific as possible. It probably one of three things:

• Incorrect RAM
• Failed RAM
• Unseated RAM

Try 12 GB instead of 16 and see if that works. I do recall there was an issue with the 2009 machines addressing 16GB though, I don't know if there was an outcome or not. If you haven't run Software Update in awhile you should to see if there have been any update you may need. 

Roger asked you to give the exact specifications of the new Ram that you have bought. Can you inform us with those please?

slinxy wrote:

 

Crucial 4gb ddr3 1333 pc3-10600

You installed the wrong RAM, a late 2009 iMac calls for:

you mistakenly got 1333 which is probably what the issue is.

Indeed the wrong Ram: if you have higher speed Ram than the bus, it will be downclocked (may work), but in your case the downclocking did not work when there is no original Ram at all. It is very important to have exactly the the right specs, otherwise you will be plagued by kernel panics.

Send the Ram back and ask a replacement with the correct spec.

Lex

BTW: Crucial is a very good and respectable company, they have a configurator on their site!

You do not understand: the iMac needs 1066MHz, you said that you have bought 1333MHz !!! That means that you now have the wrong Ram in it: read my and Roger's post !!!

As Lex said you installed the incorrect RAM!!!!!!!!!!!