i ordered an i5 3.1 27 inch from the canadian refurb store.

supposed to come with the standard set-up, but came with 8GB of RAM, not the 4GB of RAM that was on the invoice! Funny thing is that I ordered 16GB of third party RAM to install and remove the original 4GB standard RAM.

How much RAM can i put into this puppy?

You have four memory sockets in the new iMacs, so you can install up to 32 GB RAM ( 4 x 8 GB SODIMMs)

You have four memory sockets in the new iMacs, so you can install up to 32 GB RAM ( 4 x 8 GB SODIMMs)

CanadaRAM, a question for you, as I know that RAM is your thing. How much RAM is really necessary for the average user? Unless you're running a lot of queries or crunching video, is there much performance to be gained by 32GB worth?

You have four memory sockets in the new iMacs, so you can install up to 32 GB RAM ( 4 x 8 GB SODIMMs)

Whoah I had no idea. I have 12gb right now. 32gb sounds nice... hahaha.

Anything between 4 and 8gb is enough for today's usage (average user).

In a few years, you would see 8gb as minimum in most systems and 16gb for those who are more multi task users than avg.

CanadaRAM, a question for you, as I know that RAM is your thing. How much RAM is really necessary for the average user? Unless you're running a lot of queries or crunching video, is there much performance to be gained by 32GB worth?

There is a diminishing marginal return on more RAM. You don't get the same improvement when going from 8 to 16 that you got from moving from 2 to 8 GB, and (for heavy users) not the same amount of improvement from 16 to 32 as you did from 8 to 16 GB.

The key is having ENOUGH RAM for what you are doing.
Anything less than Enough and your machine has to resort to writing swap files on and off the harddrive, which slows everything down.
Enough RAM varies with what you are doing. If you are multitasking heavily, then you need more RAM.

Adding RAM up to the Enough level is like taking your foot off the brake pedal of your car. It doesn't make the car faster, but it does stop slowing it down.

It's a special case if you are using Photoshop, doing heavy graphics work, engineering/3D or using any audio, video or multimedia production software. Many of these programs can take advantage of extra RAM in their own data caching schemes to run faster.

A quick way to check if one is maybe a bit short of one's Mac memory is to occasionally open Activity Monitor and have a look with the 'System memory' tab selected.

Usually if any 'page outs' or 'swap' stuff is listed, then maybe a lack of installed RAM could be the cause.

There is a diminishing marginal return on more RAM. You don't get the same improvement when going from 8 to 16 that you got from moving from 2 to 8 GB, and (for heavy users) not the same amount of improvement from 16 to 32 as you did from 8 to 16 GB.

The key is having ENOUGH RAM for what you are doing.
Anything less than Enough and your machine has to resort to writing swap files on and off the harddrive, which slows everything down.
Enough RAM varies with what you are doing. If you are multitasking heavily, then you need more RAM.

Adding RAM up to the Enough level is like taking your foot off the brake pedal of your car. It doesn't make the car faster, but it does stop slowing it down.

It's a special case if you are using Photoshop, doing heavy graphics work, engineering/3D or using any audio, video or multimedia production software. Many of these programs can take advantage of extra RAM in their own data caching schemes to run faster.

Great answer, much appreciated.