Problems with my newly built I3 Pro B

[Syzygye]

I have an i3 Pro B with a gt2560 board. First I had an issue with the x axis being reversed, a firmware tweak took care of that. The X axis moves fine on it's own, but when I go to print, as Y moves it sort of loses it's oomph and refuses to move away from where it is sitting. But it has no issues moving backwards towards the endstop that it doesnt trigger (it does when I home it, but not in this situation) When I swap the x and y motors on the board, i get the same results with the Y axis, so It's a firmware or board problem. Also worth noting, it's not 100% stable (The X axis on the board) When I attempt to move it by -50mm, it will say it's moving by -50... or -5 in the software, but do nothing physically. This happens to both the y and x motors on the X axis pins and only when moving -xx never when moving +xx and not 100% of the time.

[Syzygye]

http://puu.sh/oTGPw/eb4d30b3b0.mp4

a video of the problem. I moved the extruder to the opposite side to show what's happening instead of having a video where it grinds against the endstop (which triggers at all times except for when I print, despite my slic3r settings being properly configured) This video was recorded before I changed the firmware settings, but the behaviour is the exact same.

[Admin]

http://puu.sh/oTGPw/eb4d30b3b0.mp4

a video of the problem. I moved the extruder to the opposite side to show what's happening instead of having a video where it grinds against the endstop (which triggers at all times except for when I print, despite my slic3r settings being properly configured) This video was recorded before I changed the firmware settings, but the behaviour is the exact same.

if it is not the problem of the axis direction, please check the stepper motor driver, can you swap the X axis driver with the Y axis or other driver that is working. I think it might be the problem of the driver board.

[Syzygye]

In my original post I state that I have swapped the x and y motor connections and the problem moves to the Y axis.

http://puu.sh/oX5ba/ee07898040.jpg - This is a photo of a failed Benchy print vs what repetier says I should be seeing - http://puu.sh/oX50r/c857866210.png

I move that same Gcode to Pronterface and while the problem is lessened, it still persists to an extent. - http://puu.sh/oXeuE/64c70fa132.jpg

I would try printing directly off the SD card, but my LCD interface is non-functional as the knob only controls the FR % and nothing else.