The sustained read/write performance of any specific drive/connection combo. If they're properly formatted and 'permissioned' through the OS, PrPro doesn't seem to give a rat's tail whether they're internal or external. I've never done anything 'special' to get the externals to work with PrPro. To the laptop (besides most of the above) I've used external USB2 connected external drives either 'spinning' or SSD from Seagate, WD, and others. a wide array of externals with PrPro without issues, both Win7 and now Win10, on both laptop and desktop.ĮSATA connection to say BlacXor Thermaltake pop-in drive boxes, USB to the same, PNY 128GB flashdrive via USB3, now a WavLink external box via USB3.