this is actually relatively normal. i see your specs, and am surprised that you notice this actually happening. but yeah... moving the mouse DOES consume processing power, and is normal. but at the same time, your specs are good enough you shouldn't even notice this.
i see the mouse you are using is wired. so, even less reason to notice this.
well... i can think of a few things.
A.) faulty USB driver. not necessarily the driver for mouse, which is also a possibility.
B.) faulty mouse
C.) faulty USB port(s)
D.) low-end USB port(s). on older systems, processing requirements are significantly reduced by using a PCI USB card. however, this shouldn't be a problem for you on that motherboard.
E.) it is always possible it is the polling rate of your mouse causing this. however, we are back to system specs... yours is good enough that it shouldn't have any noticeable impact.
F.) if you are using a particularly high resolution. i also have a GTX 1070 Ti, and it falls miles short for modern gaming at 4k+60FPS. if you are using anything higher than 1080p, i would try lowering your resolution.
the software for your mouse should have an option to change the polling rate. if not, you can try hidusb.
https://github.com/LordOfMice/hidusbf
i see your mouse supports 1000 polling rate. however, do be warned about using hidusb to overclock a mouse... if the mouse isn't designed to run at a high polling rate, you could burn out the sensor inside.