I’m having the same issue. Here are the specs for my pc and friends laptop:
My PC
Intel Core i7 3770K @3.5GHz
RAM 32GBytes 1333MHz DDR3
NVIDEA GeForce GTX 660 Ti
SSD SAMSUNG 830 SERIES
FRIENDS LAPTOP
Intel Core i7-4900MQ Processor (Quad Core, 8M Cache, 2.8 GHz, w/HD
RAM -8GB (2x4GB) 1866MHz DDR3L
-NVIDIA Quadro K2100M w/2GB
-SSDR HD 256GBÂ
His laptop is getting super smooth scrubbing with the exact same footage running off the same external drive. It’s pretty frustrating seeing how premiere should perform and not knowing why mine isn’t.