I'm running a b250M mobo with a i5 6600k stock. I had some cheap branded green sticks of ddr4 ram (4gbx2) but I don't remember the name. I recently got a used pair of corsair vengeance 3200mhz (8gbx2) ram and put it in to my pc.

Bios says 2133mhz is the highest it'll go, with or without xmp. The mobo apparently supports 2400mhz. However, that doesn't really bother me much. The old ram was probably also running at 2133 mhz.

When playing dota2 on windows (full screen mode), I noticed if I have a alt tab my mouse over to my second monitor, everything is really choppy. I don't remember this happening with my old ram.

My no man's sky game has also gone from playable to choppy, but there was an update as soon as I installed my ram, so I'm not sure. I'm also running a amd r7 370 gpu, so that could be the reason, not sure.

I flashed my bios with the latest firmware and also reset all the settings to stock.

The only thing that changed recently was the ram, anything obvious I should look at? Is the ram bad? Does ram have to support my cpu/mobo?