Nvidia has once again decided to prevent some notebook owners from overclocking their Maxwell-based GeForce GTX 900M GPUs, after removing the restriction in a March driver update.

According to many members of the NotebookReview community, as noted by TechPowerUp, Nvidia silently re-enabled the block on GTX 900M series overclocking in the 350.12 driver update last month. The restriction, nicknamed the "clockblock" by affected users, is still present in Nvidia's latest 352.86 drivers that were released earlier this week.

The restriction currently affects those with a locked GPU vBIOS, which essentially prevents overclocking at the BIOS level on some systems. The latest models of some Nvidia-powered gaming laptops, such as the 2015 Alienware series, ship with this locked BIOS, making it impossible to overclock without reverting to an older BIOS or using a mod.

One of Nvidia's older driver releases, 347.88, removed the overclocking restriction even for those with locked vBIOSes, following community backlash after the blocking was implemented with Nvidia's 347.09 drivers. This latest re-implementation of the overclock block on 900M series cards continues Nvidia's see-sawing policy regarding mobile GPU overclocking.

For anyone affected by the overclocking restriction, reverting back to the 347.88 drivers will allow you to overclock once again. However, as this driver is several months old, you'll miss out on the latest code optimizations for new games such as Grand Theft Auto V and The Witcher 3: Wild Hunt.