Hi jnorris.
I have the same model PC and I upgraded the memory to 32GB. I'm using 2*16GB 3200 memory sticks and I have zero issues. I believe the PC is designed for 2400 but when using 3200 memory, the memory is not running at 3200. You will not be seeing any performance increase. It was easier for me to get the newer 3200 than the older 2400.
Hope that helps.