Apple users have speculated that the new iMac lockups were products of bad software design (hence Apple's attempts to update the software), but new discoveries pegged these reasons as unfounded. Instead, evidence began to point at the hardware side of Apple's iMac line, and graphical anomalies hinted that the graphics chip was at fault.

The embedded ATi Radeon HD 2400 XT (with accompanying 2600 PRO) graphics processor unit (GPU) stood as the iMac's current video engine, and it was singled out in particular. Users said that some defective iMacs were also exhibiting graphical artifacts - the same artifacts that hardware enthusiasts would encounter after overclocking their GPUs a tad too much.

Heat dissipation is the prime reason for the graphical artifacts, but currently there haven't been no permanent solution announced or implemented by the company. Apple is still investigating the lockup issues, and it has yet to respond to these new finds.