I am going to be housing large data sets on an external hard drive. From it I will be doing a lot of reading/writing as I process data from my laptop via a USB 3.0 port.
what should I get to make this run fast when using it. Will there be a bottleneck caused by using a USB cable that will make other factors relevant to speed inconsequential?
USB3 has a higher transfer rate than any mechanical HDD so there is no bottleneck from it.
Other choices would be an external HDD with eSATA and if there are multiple devices that may need access to the data sets, NAS with Gigabit would be recommended as well, I’ve found that Synology makes great performing NAS Devices with single to 8 HDD units. They are expensive but worth every penny and perform better than most other NAS boxes out there.
But in terms of USB3, Your HDD will be the bottle neck on this so if performance is really a critical piece to your puzzle, find a USB3 enclosure and throw in an SSD for the max performance.