gpuimac
I have a weird issue with my iMac 2011 model. This is the iMac with the graphic card issue, so it happened to me as well.
I tried everything except baking the graphics card, this is my absolute last resort. What I've done now is I installed Windows on the iMac, and guess what it works perfect, please don't judge but this was only for testing.
So now, why is it that Windows works but not OSX?
Does anyone have any thoughts on why this is? Please do let me know.
Much appreciated.
No you are correct there are no upgrade options available for the 21.5" iMacs (Mid-2011). Yes, you are stuck with what comes in each of the two 21.5" models available. Your eyes are not deceiving you on the iMac Specs, what you see is what you get no exceptions.
You graphics card options are:
According to MacWorld's article / review "21.5- and 27-inch iMacs (Mid 2011)"
So in reality you have two options, and its all in which machine you buy. If all you want is a graphics boot, your going to have to pay the premium to upgrade all the other components too, unfortunately there is no way around it, other than letting apple know you want options, give them some feedback stating so.
To determine if it is your hardware or OS X boot from external drive. If it works it is your OS X, if not, it is your hardware.
If it is OS X use Safe mode and:
sudo kexstsat in Terminal (enter password)
Best Answer
You need to repair/replace the GPU card.
If you're going to bake it, you may as well just toss it into the bin and save the electricity/gas used to heat the oven. Baking a PCB is about the worst thing you can do because...
it assumes that the issue is a dry solder joint which the theory is re-flowing the solder will somehow fix the problem. It ignores that the problem may be something simple like a bad capacitor, resistor or some other component. Re flowing doesn't fix any of this
you're literally cooking the components on the board so if they weren't bad before, they're likely to be bad now.
Why not judge? That's a perfectly viable, creative way to test the viability of your iMac. You got Windows working so you can see that from a hardware perspective, you've got a working machine (well, almost). Nothing wrong with getting test results that give you definitive answers.
It's integrated graphics versus dedicated (discrete) graphics. The Intel Core CPUs have integrated graphics chipset (i.e. HD Graphics, Iris, etc.) as well as a discrete GPU like the Radeon HD 6970M (mobile chip). When you boot into Windows, it defaults to the integrated graphics whereas macOS is likely set to use "both" integrated and discrete.
How to fix...
You've got two options
The board itself can be repaired. There are shops that do board level repair. They can diagnose and replace the specific components that have gone bad.
Replace the GPU (link is about upgrade a 2009/2010 iMac, but it lists all 2011 compatible GPUs) It may be quicker, easier, and possibly cheaper to simply swap out the GPU with another. If you go this route, don't toss the bad GPU - you may be able to get a few dollars in scrap value from a board repair shop.