iMac late 2009 27" HW upgrade with Mid 2011 parts

[Chris070]

Hi all,

I am looking into upgrading my old iMac Late 2009 core i7 27-inch with 32 GB (1066 MHZ DDR3) RAM, OWC SSD as a startup disk + 2 TB HDD, running HighSierra.
The current logic board is having issues and needs replacement. The original graphic card (ATI Radeon HD 4850) won't run on Mojave or Catalina.
I have the following questions:

- Does somebody have any experience with replacing the late 2009 logic board with a logic board of an iMac Mid-2011 "Core i7" 3.4 27-inch? will it fit in
the late 2009 casing and are there be incompatibilities with other internal components such as: power supply, RAM memory but also physical
connectors?

- Could you possibly advise a graphic card that will run Mojave and up?
I have read about compatible graphic cards which do not have the Mac VBIOS running. As a result, no backlight control from the
keyboard.

Apologies for the very technical questions and thanks in advance for anyone 'support ?

 

[Ausdauersportler]

The 2011 board does not fit into the 2009/2010 case! It has one more mini display port and there is no fitting hole in the case.
Try to get a complete new old 2011 system.

There is a complete thread about changing graphics cards in 2009-2011 iMacs - one search away

 

[Chris070]

The 2011 board does not fit into the 2009/2010 case! It has one more mini display port and there is no fitting hole in the case.
Try to get a complete new old 2011 system.

There is a complete thread about changing graphics cards in 2009-2011 iMacs - one search away

Many thanks for your answer Ausdauersportler very helpful!
I will look into the thread about the graphic cards.

Last question: you mentioned the "2009/2010 case" does that mean that a 2010 logic board fit into a late 2009 27 case? there are slight differences in performance and the 2009 RAM memory 1066MHz would need to be replaced with 1333 MHz but if it fits, it could be worthwhile...

Default option is to replace the 2009 logic board by another 2009 one.
I am still happy with this 11y old iMac that I have been tweaking/upgrading along the years.
It still does the job ?

Thanks again!

 

[Ausdauersportler]

Please forget this upgrade idea! The late 2009 and mid 2010 share the same CPU gen, but some 2010 boards (the i5 and i7) have a new display connectors type in use. So you end up in changing more parts for more money than a 2011 with a broken GPU might cost today.

Additionally you see only minor performance differences only visible in artificial benchmarks when moving from one i7@2,80GHz to another running at 2,93 GHz. A bigger step will be going on the 2011 sandy bridge CPU.

The RAM performance depends on the modules you use: Exchange the 8500 type with a 10600 oder 12800 type and your will get the 1333MHz - this old logic board are really well designed. The 2011 will need 10600 or better. But again, the gain is probably not worth the money invested unless you sell off the old memory at a good price. You may check this by just putting in one or two cheap 2GB 10600 modules...

 

[Chris070]

Please forget this upgrade idea! The late 2009 and mid 2010 share the same CPU gen, but some 2010 boards (the i5 and i7) have a new display connectors type in use. So you end up in changing more parts for more money than a 2011 with a broken GPU might cost today.

Additionally you see only minor performance differences only visible in artificial benchmarks when moving from one i7@2,80GHz to another running at 2,93 GHz. A bigger step will be going on the 2011 sandy bridge CPU.

The RAM performance depends on the modules you use: Exchange the 8500 type with a 10600 oder 12800 type and your will get the 1333MHz - this old logic board are really well designed. The 2011 will need 10600 or better. But again, the gain is probably not worth the money invested unless you sell off the old memory at a good price. You may check this by just putting in one or two cheap 2GB 10600 modules...

I 100% convinced! Thx a lot for your enlightenment?. I just thought I'd boost the old beast a bit more but I will stick to another late 2009 core i7 logic board which is fine after all.

Next step is to focus on the right GPU that will enable me to upgrade from HighSierra to Movaje/Catalina but this promises to be a tough challenges if I read all the docs around...

 

[Ausdauersportler]

Just read the first post on the first page of the thread - it is our secret and well hidden guide including a support list