4mem/61/40000000: 0xbac41d18

Run the test with one RAM module installed and then the other.

see > https://support.apple.com/en-us/HT201191

Once you have isolated the bad module.

Replace it, or better yet, replace both with a new pair of compatible RAM modules.

see > https://eshop.macsales.com/shop/memory/iMac/2010/DDR3_21.5_27

You're welcome. Let us know what you find.

Good work.

Is it one of the original modules or one of the aftermarket modules?

Also note that some suppliers OWC, Crucial and others, have a lifetime guaranty. and will replace the module.