So I've gotta brag on Repetier-Host  I'm sitting here on a 1.6ghz ATOM processor,

So I’ve gotta brag on Repetier-Host I’m sitting here on a 1.6ghz ATOM processor, 2gb of memory netbook. The thing is dog slow, can’t even keep up with my typing because I’m upgrading/compiling a bunch of perl modules, have G+ open, yet somehow Repetier-Host just keeps on pumping out the Gcode to the controller for my 3D printer. I’ve not had one hiccup, one lag spike, nothing. It blows Pronterface out of the water.
http://www.repetier.com/download/

I agree it’s by far superior , but I’ve had a hiccup with it… Dunnow , maybe it had something to do with the screensaving on the mac…

@Kristof_Deruyttere a lot of screen savers, etc put the USB into sleep mode, and halt processing, etc. Almost any low-power state.

It was odd, the print started again apparently but something like 5cm away in x-axis direction…

I think the big difference is that Pronterface doesn’t seem to allow you to turn off the realtime gcode rendering. If you run Repetier Host with its (fully 3d) realtime gcode rendering enabled, it will have the same problems, but switching to temperature monitoring disables that and reduces its demands on the RAM and processor significantly.

Mac, we have found that there is a general driver issue. If the software is able to re-connect automatically, everything is fine. This might be a bit more stable with Repetier host and firmware, but will be a bit off with most setups that don’t have good feedback and error handling. Does anyone know if Repetier is doing real time position tracking? That is what we are rolling into the 5D Print USB device software, so it might even be possible to recover if stopped in mid-move and pause immediately works without running through a queue.

Repetier host shows the position slightly ahead of real time by showing the position of the last move command sent. Marlin and similar firmwares, of course, keep this in a buffer, the the actual movement of the machine is a bit behind the display. In this configuration, there is no position feedback to the host from the firmware, and I would be surprised to see any given the additional burden it would place on the serial connection (though there would probably be enough excess capacity when we get full-speed USB support without serial translation).