Mixing memory brands ?

[raver001]

I am thinking about getting 8GB Ram (x2 4gb sticks) I am getting the memory from crucial.com...

http://www.crucial.com/uk/store/mpartspecs.aspx?mtbpoid=502149E6A5CA7304

My machine is a Mid 2011 27" Core i5 3.1 iMac.

My question is, if I was to leave to 4gb factory memory in there will it work as 12gb even though there will be two different makes of memory in the machine or is this not recommended?

 

[mjsidebottom]

Mixed Memory

Care needs to be taken as some manufacturers are better than others.

Obey all anti-static rules when fitting memory.

It is best to use memory specified for your model of Mac.
I have used memory from Crucial.com or co.uk with 100% success for the last 5 years on mine and Clients Macs.

 

[The-Pro]

The machine doesn't care. Get the same speed of RAM though. The RAM will work together flawlessly no matter the brand.

 

[drambuie]

As long as the speed (MHz) and timing (CL) is the same, there should be no problem as long as the two makes are in different banks. Although there may be no problems, it is not recommended to use mixed manufacturers in the same dual channel bank. This won't be applicable to you as the new DIMMs have different capacities.

What I would do, is remove the existing lower bank 4GB and put the 8GB in its place. This will give a continuous 8GB without bank switching, but more importantly, will allow you to test the RAM in normal use. Applications will mainly run in the lower bank, so the upper bank wouldn't be used unless you had large apps with massive data, such as Photoshop with multiple large bitmaps open. You can then reinstall the 4GB in the upper bank.