What does 4MEM/60/40000000: 0x8495d198 error mean?

You could try reseating them first, and run the test again. It's a pain, since you have to keep opening your laptop to test. It might be safer to just replace the failed piece. 16GB (2 x 8GB) is unfortunately the maximum.

Hi,

It may be a RAM issue or an issue with one or both of the slots, or the logic board. You can "test" the RAM and slots.

If you have replaced the original RAM, it is best to reinstall it for test purposes. The RAM is mounted in two slots. To test out one RAM module at a time and one slot at a time, remove one of the modules and try running your Mac. If the issue is gone, then the other RAM module or slot is bad. If the issue persists, move the module to the other slot and trying running again. Repeat this process for the other module. In this way you should be able to identify whether it's one/both of the RAM modules or one/both of the RAM slots.

4MEM/60/40000000: 0x8495d198

Memory error ie RAM or bad bank. Proceed as described above.

No, you can not run 2 x 16GB or everybody would already be doing it.

If you have to order new RAM, best to run with a match pair of modules.

Try OWC Memory Upgrades For MacBook Pro 2011 - 8GB, 12GB, and 16GB

You're welcome. 🙂 Hope you'll post back with results.