Buy a USB extension cable to keep your keyboard closer to the dongle. Solved my problem right away.
Public Service Announcement
I absolutely love my Microsoft Sculpt Keyboard. The function keys are a bit flimsy for my taste, but in my opinion it’s still the best keyboard available in its price range. The only other options I’d consider viable alternatives are triple the cost. So it was especially disappointing a few weeks ago when I built a new PC and promptly discovered that my keyboard was constantly losing keystrokes, intermittently becoming completely unresponsive, and lagging upwards of several seconds in between key presses. Aggravating, to say the least. It was also confusing, because my new tower was no further away from my keyboard than my previous tower had been.
I tried updating drivers, reinstalling drivers, and ran the Windows 10 troubleshooter on the ‘Wireless Keyboard filter Device’ and ‘Microsoft Wireless Transceiver’. This got me nowhere. The drivers were all up-to-date, reinstalling didn’t help, and the troubleshooter kept telling me something along the lines of blah blah blah ‘microsoft wireless transceiver mouse and keyboard driver is an older usb device that doesn’t work with USB 3.0. Try using a USB 2.0 port.’ Except I was using a USB 2.0 port.
After more hours of research than I care to admit, I found a few comments here and there from folks who advised getting a USB extension cable to decrease the distance between the wireless dongle and the keyboard. I resisted giving this a shot because 1) I didn’t want to drive to BestBuy and 2) I never had this problem before and was convinced it was a software problem. Finally - exasperated that no amount of research revealed a better solution - I drove to BestBuy and picked up a extension cable. I was both surprised and relieved to find that all the lag immediately disappeared.
Originally, the dongle was about four feet away from my keyboard. With the extension cable, the gap is only about 18 inches. I cannot explain why this problem only existed on my new tower. All I can think of is that the case’s composition somehow interferes with the signal. At this point I don’t really care any longer. The problem is solved and I can finally enjoy my new PC in all its speedy glory.
Hopefully this post will save other folks the hours of frustration I experienced trying to resolve this problem.