Lag time when pressing play after PC has been idle.

Hey Folks,
 
There is a lag time of 5 seconds or so when I press play after having been away from an open project for awhile (an hour or two). This is by no means a big deal - just an annoyance, but it never used to happen, so I thought I'd run it past you guys to see if you had any thoughts as to what might be causing it and whether there's anything I can do to correct it. 
 
I'm not exactly sure when it started, but I don't recall it happening with X1 or any other previous version, so probably sometime within the last 9 or 10 months. Any ideas? A Sonar setting? A Windows setting?
 
Any insight will be greatly appreciated.
 
Thanks,
Ben

Hey, Bibs. Thanks for the tip. I'll check when I get back.

Thanks, CJ. I had Power Options set so that the PC never went to sleep and the display never dimmed or turned off, but when I opened up "Change advanced power settings", I could see that, like Dibs suggested, hard disks were set to go to sleep after 20 minutes of inactivity. I didn't notice a setting for USB/FW (though I wasn't looking for one) and I'm away from my studio PC again, but I'll check that out later.
 
Thanks, guys.

gswitz
Virus scanner having to approve access to your wave files?

No.

chuckebaby
I didn't notice a setting for USB/FW (though I wasn't looking for one) and I'm away from my studio PC again, but I'll check that out later.

IIRC , its in your device manager.

This is an outside reach... the USB power setting...
 
Go into power settings > Power plans > Advanced > USB > and set them to not sleep the USB Devices.
 
Perhaps this is making a difference?? I'm totally reaching just hoping to hit on something that helps.