What in the world are you talking about?
Thank you for that.
no one is scrambling to upgrade the GPUs in these, however.
2012 and later models have integrated graphics.
Have you actually installed Mojave on a 2010 iMac? I have on my second SATA drive for my 2010 i7. I have to agree with Dosdude: Mojave is useless on these without graphics acceleration. In addition, it doesn't like to update. BTW, I find an i5 way too slow for my needs—and yes, I have one to compare.
Radeon 4xxx (not 5xxx and 6xxx however) have full hardware acceleration in Mojave with Dosdude's patch.
i5 -- Horses for courses.