Input lag after loading program

After loading a program manual jogging is delayed. After jogging PP generates a new preview. If I jog again while it is generating the preview there is a delay in motion on the machine. After the preview generates PP instantly completes the moves that were keyed in while it was generating. It then generates a new preview and te cycle continues. This can be very bad if you don’t know it is buffering and move toward the workpiece because when it’s ready the axis moves and finishes whatever input was given while you were holding the button wondering why it’s not obeying your command. I have the PP operators console and the machine is new (less than a year old and has 4gb of ram). I frequently run large programs (more than 1.5 mb. I usually increase the set_preview_limit 300000 . Do I need more ram? I havnt been doing this long but an 2mb program doesn’t seem like it is very large. I use fusion360 and I use all the instruction saving options like smoothing, g-code for arcs and such.
Anyone know what’s going on? And how to fix it?
Is this a warranty issue?

Does your machine lag without increasing the preview limit? If it lags with the default preview limit, then I would be more concerned.