Hello
I am pretty new to all of this so the problem could be anything.
When running the gcode the machine will shake, shudder, and slow down. I pretty much just make skis with my machine. The problem is most prevalent when the machine is going around the tips and tails of the ski running lots of code. When cutting down the sides it will speed back up and shudder less.  It gets worse the faster the feedrate to the point it will not achieve the maximum feedrate in the g code
My machine will jog around all day at 2400(metric). I can run gcode that fast as long as there are not too many movements at once. When doing the outline of a ski i can have a  feedrate of 800-900 maximum with no noticeable problems. Anything more and it starts to shutter. If i set the feedrate to 2000 it will get to about 1400 and shudder and shake allot.
Machine is
Ethernet smooth stepper
G540 driver
Mach3
windows 7
laptop 2.27ghz 4gb ram

Any help would be much appreciated.

The problem is most prevalent when the machine is going around the tips and tails of the ski running lots of code.

Perhaps take a look at your CAD/CAM software and it's post processor.

If you are using Arcs for the curves then the subsequent machine movement will be smoother than if you are using lots of straight lines for the curves. 

Tweakie.

Are you using CV Mode, or Exact Stop mode.
If your in CV mode, try turning off all the CV options (CV distance, CV Feedrate, and all the CV options on the General Config page.

Thanks Tweakie! It seems to be a CamBam issue. I ran the same part through LazyCam, witch i have never used, and it worked great. It will cut as fast as the machine will go and wont slow down at all. I tried CamBam's arc removal tool but it does not make any difference in speed. It did remove all the shake and shudder but it still wont go beyond 1200 feed. It also whent from 6200 lines of G code to 15,000 lines.     
Thanks for the help. Soooo much to learn with these things.