Looking at both memory readings. Right now, they are at 2 gig 1.8 gig and commit set to 1.9 gig.
Thinkorswim for example, a java app, using only 1 gig , and I have quite few windows open . Of course they don't cache all the data, I get that.
If I was running only MT, cpu usage would probably not be an issue, but the spiking to 50% every few seconds , even on a quad core, does seem to cause performance issues. Not sure how much control you have of this , in whatever dev platform you're using.
Normally I wouldn't care, but I'm noticing other apps lagging because MT is taking up so much cpu. For example , moving the cursor in TWS (IB) gets slow.
As for firefox, I don't think theres a direct connection , but it looked like MT ran better when FF was closed. Who knows. I created a new clean profile in FF just in case there was something in there causing some system slowness.