“The same results” means that your desktop is slower using the 1080 vs. your laptop with a 1080?
If so, I would profile your code and check it for other bottlenecks besides the GPU. E.g. in case you are using a fast SSD in your laptop vs. an old HDD in your desktop, the performance of the data loading pipeline would tank.
EDIT: you could also profile the achieved memory bandwidth on both systems for the GPU and check, if the used hardware is a limiting factor (e.g. by sharing the PCIe connection etc.).