My experience with FRO
I was using Mach3 controlling a SX3 with a 600MHz HP computer fitted with 1/2 G Ram, running XP SP2. I experienced occasional pauses at any feed rate, and tracked it down to the low level driver emptying the queue because the CPU was off in the weeds doing something else, and was not keeping the queue charged. If the queue gets emptied, all axis movement stops, and if the axis movement was fast enough the abrupt stop can cause loss of steps.
That said, just the act of using the mouse to change the feedrate with the +/- keys can break the bank. Clicking on a new place on the green bar seems to cause the least amount of problems.
I have since upgraded to a 1.4GHZ computer form a later junk pile, using 1/2G RAM and Win2000 (which does not go and do stupid unstoppable XP weed munching) and can do anything with the FRO now.
One thing that still gives grief, and this is a software stuff up, not the queue being emptied is if you hit the to pause, the current motion may be in the queue, the machine stops as requested, but when you hit cycle start, it MIGHT move too fast to the end of the move that was executing when paused. Great way to kill tiny cutters. I only ever stop it while cutting air, or sprinkle liberal M1's in the code so that it can be paused. I use very tiny cutters quite often.
Some don't do's with
Never pause during a peck drilling cycle
Never pause during a circle.
If you have to pause very close to the end of a move.
Another thing that helps with FRO load, is disabling graphics display, and any other CPU intensive operation, like a camera view or sound.
Another thing that will screw up the queue feeding is CAM generated sequences of vectors all in the same direction like:
G1 X2
X2.2
X2.4
X2.6
... etc (Thats really dumb code generation)
Like as though somebody used their old dot matrix algorithms.
Should be:
G1 X2
X2.6
...
What CPU/RAM/OS combination are you using.
Beware of overheads caused by badly driven video cards.
If your mouse movement is jerky that's a sign of problems.
Maybe you need to run the Mach3 speed diagnostics.
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.