In case that your computer becomes slow, even almost unresponsive for a while when you exit sleep mode, your problem may be easily fixed.

A very probable reason, is that some of your open apps causes this problem. What programs are running when you are entering sleep mode? Try closing them one by one the next times that you activate sleep mode and find out the problematic app. For example, it is known that sometimes Thunderbird can cause this problem. If you have Thunderbird running before you enter sleep mode, try closing it before sleep and see if that fixes the problem.

Another reason can be your “Power and Sleep Settings”, configured in a way that your PC needs some time to really wake up. If you wish to sacrifice a bit of your power to enjoy a snappier PC, try changing your power settings. Go to Settings > Power and sleep > Additional power settings > Change plan settings > Change advanced power settings. Then change your plan to High performance, and, at the “Sleep” section, enable Hybrid mode, disable hibernation if it is enabled, and finally enable wake timers.

Another probable reason is malfunctioning drivers or hardware, but if your drivers are updated, you may face some difficulty locating hardware problems. Let’s hope your problem is solved by one of the above ways.