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Take your performance to a whole new dimension with the PSR-SX. Replacing the hugely successful PSR-S series, the PSR-SX900 is the new generation in Digital Workstation sound, design and user experience. These instruments will inspire and intensify your musical performance and enjoyment.
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I cannot be specific for Yamaha (I would not buy the any SX model as I much prefer Korg) and with Korg systems installed content such as User Data / Registrations etc that can be overwritten.
Hence with a Korg Pa it is usuable to create a full Backup file and a Save All file where the Save All file contains the User Data then when the OS is updated the Save All file is loaded and all User Data restored.
Check with the Manual and actual SX900 owners what they have to say is the correct process to run on an SX before any changes are made.
There is a specific Yamaha PSR forum as their is a Korg specific forum and you may wish to check and compare both manufacturers models