2011 Model becoming unresponsive

Did it start after you installed the new ram? If so I'd suggest memtest run in single user mode. You could set it to go through five cycles or so overnight. Other than that I'd check activity monitor during periods of unresponsiveness and describe what you were doing.

Typical things that cause unresponsiveness include hard drive access, an application hogging cpu cycles, and bad or insufficient ram. Out of software spotlight indexing is one of the most common irritations. I'd reboot your computer. Look at activity monitor at the first sign of sluggishness. Screenshot it if necessary. For cpus view "all processes". For ram you're looking for page ins vs page outs. Provide me with some more details on this stuff and perhaps I can help you figure out if it's a simple problem.

 

are you Savy enough to open the bottom and remove 1 stick of RAM at a time to see if you have bad RAM?

 

That seems like a quicker way to check for a faulty stick if you don't want to do the memtest. This would give you the most broad/general test to see if your memory is ok, I bought 8gb OWC memory maybe a week ago and its worked great. Fortunately if you do have bad stick(s) the lifetime guarantee from them will set you right, Ive had no problems with the ram, fingers crossed.

So this hanging system problem happened immediately after the upgrade?

 

yes if its still doing it with either of the sticks than try your original RAM

 

Even though OWC is a reliable brand, it's always possible to get a bad chip. Since it started around the same time you upgraded the RAM, that's definitely the first thing to check.