OS: Arch Linux
Hardware: Notebook ASUS F8Vr, CPU Intel Core 2 Duo P8400 2.26GHz, 4 GB RAM, Mobility Radeon HD 3470 (RV620)
After update kernel from 4.6.4 to 4.7 I found artifacts when KMS activated - blue dots drop down in console and graphics mode. Downgrade to 4.6.4 - not found any artifacts. Upgrade to 4.7.1 and 4.7.2 - artifacts is found. When I disable KMS with 'nomodeset' kernel parameter the artifacts disappear.
Fix on it's way upstream already.