The 27″ iMac are still good computers used by photographers and graphic designers but not only.
With a dedicated AMD Radeon VGA card that can be:
For 2009 models:
– 3.06GHz
– ATI Radeon HD 4670 graphics processor with 256MB of GDDR3 memory
– ATI Radeon HD 4850 graphics processor with 512MB of GDDR3 memory
– 2.66GHz
– ATI Radeon HD 4850 graphics processor with 512MB of GDDR3 memory

For 2011 models:
– 2.7 GHz
– AMD Radeon HD 6770M graphics processor with 512MB of GDDR5 memory
– 3.1 GHz
– AMD Radeon HD 6970M graphics processor with 1GB of GDDR5 memory

The main problem with all the iMacs is the overheating. After a period of time, that can be less or more depend on the factors like the environment, they start to overheat due of dust that is building up on the fans and heatsink. One of the signs that the system starts to overheat is a noisy fan, the fans are starting to spin faster than normal making a load noise. If you notice that happening with your system then definitely you need to have it serviced. If you continue to use it like this most likely he’ll end up with a defective VGA. Tha’s wat happened with this customer’s iMac.iMac 27 with bad VGAThe bad news is that all the devices older than 5 years are considered by Apple vintage¬†products and they don’t service them anymore. The good news is that here at ComputerLand we can fix any device no matter how old it is.

You can see the following images with the dusty fans:

In order to repair the video card, we have to remove it. See the pictures:

After we have the VGA repair done, the next step is reasemble the iMac and test it.