I don't have any lockup issues, but I have noticed Core 1 and Core 4 both are used pretty much in sync. I have a CPU gauge in my status bar, and on 4.3 Core 1 would alway be active the most. Now on 4.4.2 I see Core 1 and Core 4 both used about the same, and at the same times. All four get going pretty good faster now too. It's having no effect on my battery, but the phone is running much smoother overall, so I'm very happy with it.
Moto Defy Green Lens - CM 7.2 / Android 2.3.7
Moto Defy Red Lens - CM 7.2 / Android 2.3.7
Nexus One - CM 11 / Android 4.4.2
Galaxy S II - CM 10.2 / Android 4.3
HTC Desire HD - Stock GB / Android 2.3.6
Galaxy Note 3 - Stock Rooted KK / Android 4.4.2