Computer gets slow when pynq board is powered on


I am using the pynq-z2 board and a Dell desktop (Windows 10, 8GB RAM). I am using prog UART to flash onto the FPGA and PMODA pins for UART communication with the PC (I have UART to USB converter at the PC’s port). I am also using the 5V IO on the Arduino IO pins to power a PCB.

When I switch on the Pynq board (using PSON_SW), the system hangs up for quite a while before I am able to use any inputs. What could be the reason for this bug/glitch?