Two systems, one issue with GPU usage

[Zev_7]

I have a laptop with an i7 8750h, GTX 1050 Ti 4GB max-Q, 2666mhz 16gb ddr4 Ram, and a 1080p 60hz display
During gameplay (killing floor 2) my RAM usage on both systems is 8gb, but on my laptop my GPU uses only 2gb vram? 
Currently it does not get the same amount of lag as my desktop, it's actually very stable

On my other desktop system, i have 1600mhz 16gb DDR3 ram, GTX 1060 3GB, 650 Watt PSU, i5 4670, and a z87-k mobo
Except this system has a 144hz 1080p display and another 60hz 1080p display (although i had it off but still plugged in at the time)

Today and occasionally i get drops in FPS on the desktop system, and i tested it today for a couple minutes and found GPU utilization to be 100% and using more than 2gb of VRAM which was causing terrible FPS. 
Temperatures were normal, so what gives? 
Both systems have the same OS, not all the same number of apps but still pretty close, so what could be the issue?

The only thing i can think of is that my laptop has a better CPU, CPU Clockspeed, and higher RAM speed plus the newer architecture. 
Pushing 63 FPS is more demanding than just 60 FPS but common that's not really differential

Because i feel like getting better FPS in killing floor 2 and in general to get 144hz, what should i upgrade to?
i only have $472
For budget purposes i was thinking 16Gb DDR4 2400mhz, i3 8300, Asus strix H370-F, and the same GTX 1060

OR do you think i should get a better, used GPU to fix that issue?