This app shows if your CPU has been slowed down.
Tap the hamburger icon in the upper left > Tap this device > Tap CPU > If the CPU actual clock equals CPU Maximum clock, then it's not slowed down.
Lirum Device Info Lite by Rogerio Hirooka
https://itunes.apple.com/us/app/lirum-device-info-lite/id591660734?mt=8
Tap the hamburger icon in the upper left > Tap this device > Tap CPU > If the CPU actual clock equals CPU Maximum clock, then it's not slowed down.
Lirum Device Info Lite by Rogerio Hirooka
https://itunes.apple.com/us/app/lirum-device-info-lite/id591660734?mt=8