Alright, awesome thanks guys!
Will definitely be working on optimizing all my plots over the next few days :)
You need make optimization (need the same free space) or replot it in direct mode with GPU or replot using XPlotter (CPU)
The drive was plotted using the GPU Plotter on buffer.
And no I don't believe its USB 3.0 :/ @Vneck
Ah that's it. Yes, you need to optimize the plots. You can run the plotsoptimizer program to optimize the plots, pending extra harddrive space, or you can re-plot using the GPU with Direct or the Xplotter like @haitch mentioned.