I would like to upgrade the RAM in my 2006 iMac from the factory supplied 1GHz to either 2 or 3GHz.
I have done a small amount of reading on the subject. Is it as easy as adding a 2GHz memory module to the existing 1GHz, or is it wise to obtain matched modules?
I have discovered a convenient supplier nearby that has "Kingston" and "Certified" product. I have seen much reference to OWC in these support discussions, but not these guys.
I would recommend either OWC (www.macsales.com) or Crucial, both are very reliable vendors. OWC is a US company and ships to Canada daily so don't worry about using them. They also have terrific support including how-to videos on installing, telephone support (both before and after sales) and online chats.
Your vintage Mac can be finicky about the RAM you put in it. Stay away from Kingston Value RAM for example, however Kingston's higher quality brands seem to work fine. For simplicities sake I'd just deal with OWC or Crucial.
Here are the complete specs for the 17" model (the 20" model has the same RAM configuration):
The RAM is installed as 2 x 512 MB modules, so you will need to remove both modules. If you either want 2 GB total or 3 GB total, you will need to buy either
2 x 1 GB or
1 x 2 GB plus 1 x 1 GB for a total of 3 GB.
And I'll absolutely second the recommendation for OWC.