I'm beginning to think that this HP box has an IGPU masked as a HD4200. When I check the box on the Moo website it says the coprocessor is: AMD ATI Radeon HD 2300/2400/3200 (RV610) (368MB) driver: 1.4.1457
Says nothing about an HD 4xxx series. I wish it would run Collatz. It errors out both the mini and reg. wu's. Tomorrow I'm shutting down Moo on it and just running the 4 cores on DiRT/Prima.