If you’re a DIT then chances are you’re a computer nerd. If you’re a computer nerd then your system has an antivirus program. What you may not realize is that most antivirus programs include some kind of real-time protection; your antivirus program is scanning files as they are read and written. That’s great if you’re protecting yourself from viruses and malware, but not so great if you’re trying to copy a SxS card or RED MAG.
Disable real-time antivirus scanning or, if you can, exclude the hard drives that you’re using on set.
I use Avast! Antivirus on both my PC and Mac systems and, while being free and having a good reputation, it allows me to add hard drives to an exclusion list. Disabling real-time antivirus scanning on my field MacBook cut transfer times by a third and I’ve come across a few people who always wonder why their transfer speeds aren’t as high as others.