Earlier this month, Nvidia has disabled overclocking on GTX 900M series GPUs via the latest Geforce 347.29 driver update, and provided a rather generic explanation, stating that Geforce notebooks were not designed to support overclocking and that "overclocking is by no means a trivial feature" and users risk serious damange to the system.
While this was probably limited to a rather small crowd that is actually overclocking mobile GTX 900M series GPUs, it was still a rather important thing since users should be able to use the hardware as they want and be allowed to overclock their GPUs even if it means voiding the warranty.
Today, Nvidia apparently decided to bring back overclocking with its next driver update scheduled for March. Nvidia was quite keen to note that they "obsess over every possible optimization" so users can enjoy a perfectly stable system that balances game, thermal, power and acoustic performance but those that nejoy pushing the system even further with overclocking should be allow to do so.
Nvidia noted that those that are eager to get overclocking support earlier, should revert back to Geforce 344.75 driver.