Slow input with Logitech K350 Wireless Keyboard

I have a Logitech K350 wireless keyboard and mouse (what is sold at Sam's Club) that uses the Logitech "Unifying" USB interface. The mouse seems work OK, however, the keyboard input is slow, many times. I hit a key and have to wait for the keystroke action. It is painfully obvious on games. Just typing such as the input on this forum or in MSWord and I have to slow down as the keyboard can't...