It is not that unnormal for iMac GPUs to get hot easily, unfortunately. Make sure to clean the GPU heatpipe every few years (like 3 or so), even if you're not running in a dusty environment you'll be surprised how much dust accumulates there. You can find instructions on how to open your iMac e.g. on youtube or tell your dealer to open and clean it internally. If you are running 3d applications, think about limiting the frame rate and lowering the quality.

It is not that abnormal for iMac GPUs to get hot easily, unfortunately. Make sure to clean the GPU heatpipe every few years (like 3 or so), even if you're not running in a dusty environment you'll be surprised how much dust accumulates there. You can find instructions on how to open your iMac e.g. on youtube or tell your dealer to open and clean it internally. If you are running 3D applications, think about limiting the frame rate and lowering the quality.