If you reduce the memory allocation for the Integrated GPU, and then save changes it should then run on lesser shared memory for GPU and your system memory count should increase by that freed up. If its not working this way and your sure you save on exit, then I would replace the CMOS battery usually a 2032 and then go in and make necessary adjustments and then save settings and then reboot and it should hold with the value you specify for GPU shared memory allocation.