20 inch Intel iMac with 512 MB RAM: is an additional 512 or 1 gB stick bet

You could pull the stick out and Google the info on it.

The extra gain from matched pairs is very slight. Most of us would never notice the difference.

That being said I took out my 512 & bought 2 1gb sticks. I could not find them bundled as "matched" pairs, so I just bought two of the same. I actually just wanted to obtain the 2gb, not matched pairs.

I could take one out & put in the 512 to do my own test, but that is just plain too much work!

Now, in YOUR case; Do you need (desire) 1.5mb, or can you get by on 1gb? Do you do a fair amount of memory intensive work?

I would suggest get the 1gb stick. But, then I'm prone to over kill!

Steve

Two things will help you...

More memory & Universal Binary applications.

The first you can buy now, the second we just have to wait.

I have 2gb & Photoshop CS2 works fine. I've not done video yet, but remember all the the iLife apps are UB.

Steve

"anyone know who makes the OEM 512 MB stick and where to get compatible memory for my iMac?"

Regardless who made your OEM module, it will have a label with their name and the product specs (or at least a product number, which, on a page at their website, can be decoded for its exact specs).

Mine was made by the U.S. company Micron Technology at their Singapore factory, and the label states that the module is lead free. A similar Micron module can be purchased online from Micron's wholly owned subsidiary Crucial Technology, which is their retailing arm. Retail customers can not order directly from Micron, just as they can not order directly from either Samsung or Hynix, the other two large OEM RAM manufacturers.

"I am wondering whether an additional 512 MB of RAM or an unsymmetrical 1 GB RAM stick would be better?"

I agree that more RAM is better, will make it snappier, and prefer to buy my 1GB stick of RAM from Crucial, as I know it will be compatible for my Mac and its OEM stick (regardless of the maker) as long as I use their online Mac selector tool.

While getting matched memory will give you a slight boost, it probably isn't enough to tell much of a difference. If you must have the faster speed possible, then go with matched ram, otherwise a 512MB module and a 1GB module will work just fine.

Glor