I am using LR5.7 based on Windows 7 and got some 150 000 Photos in one catalugue. Could import, export and rendering speed be increased, if I store the LR-catalogue on the same drive like my photos? Today the programm, the catalogue and the photos are all on different drives.
The speed of export and import and rendering depends on the CPU primarily. The disk contributes only a trivial amount to the speed of export and import and rendering. You'd spend more time moving the photos than you would gain in speed.