Mixed ram size

[slp1515]

Hello,

I recently purchased a new IMac with intel i7 quad core. I requested that the standard 4GB of ram (2-2GB DDR3) that comes with the system be switched out for 8 GB (2-4GB DDR3). To my surprise when I got home the tech had left in the original 4 GB and also added the 8 GB to the open two slots for a total of 12GB.

I have read that it is not a good idea to have modules of different sizes, so is it worse to have the additional 4GB because there is now a mix of RAM sizes?

Thanks

 

[GhislainG]

As long as they work in dual channel, it isn't an issue.

 

[slp1515]

sorry to be a novice, but I am new to macs...how can i tell if they are working in dual channel?

below is information from the System Profiler:
ECC: Disabled

BANK 0/DIMM0:

Size: 2 GB
Type: DDR3
Speed: 1067 MHz
Status: OK
Manufacturer: 0x80AD

BANK 1/DIMM0:

Size: 2 GB
Type: DDR3
Speed: 1067 MHz
Status: OK
Manufacturer: 0x80AD

BANK 0/DIMM1:

Size: 4 GB
Type: DDR3
Speed: 1067 MHz
Status: OK
Manufacturer: 0x80AD

BANK 1/DIMM1:

Size: 4 GB
Type: DDR3
Speed: 1067 MHz
Status: OK
Manufacturer: 0x80AD

 

[GhislainG]

Since DIMM0 and DIMM1 are identical in each channel, they should be in dual-channel mode.