Q: Sleep mode

Hi, TopResponse.  

Thank you for visiting Apple Support Communities.  

I understand you have a concern with the time it takes for your iMac to wake from sleep.  Here are the troubleshooting steps that I would recommend for this issue.  

If your Mac doesn't wake when you expect

Your Mac might pause a few seconds before it wakes up. If it doesn't seem to wake at all, check for these possibilities:

• Your screen brightness might be turned down.
• If you're using an external display, your display might be turned off. 
• Your Mac might be in safe sleep. To wake from safe sleep, press the power button.
• Check for a sleep indicator light, if applicable, and make sure that your Mac isn't turned off.

If the previous steps don't work

These additional steps may help identify or resolve the issue: 

• Reset the SMC.
• Reset NVRAM.
• Disconnect external devices other than your Apple keyboard, mouse, and display. If that resolves the issue, gradually reconnect your devices, testing each time, until you find the device that is interfering with sleep. Then check the documentation that came with the device, or contact the device manufacturer.
• Start up in Safe Mode to see if the issue is related to non-Apple startup items, login items, or kernel extensions. 
• Try to isolate the issue by using another user account. 

If your Mac doesn‘t sleep or wake when expected

Cheers