Hi John,
I'm not sure if you are 'chain yanking' with your OP, considering the date of posting and your user name, but I'll give you the benefit of the doubt and answer!
The only real 'optional extra' storage device that can be fitted 'internally' to a Tyros5 is an expansion memory module.
This is only required if you want to install expansion voices or voice packs which use new wave samples that are not built into the keyboard's wave ROM. Any new wave samples must be loaded into the fast flash memory in theses modules.
There are only a few options available which vary by the amount of memory on the expansion module and the manufacturer.
Yamaha sell (at inflated prices!
) modules containing 512MB (FL512FM) and 1024 MB (FL 1024FM).
There is another manufacturer (Mutec) that sells it's own version of the modules in 512MB (FMC-05), 1024MB (FMC-06) and 2048 MB (FMC-07) sizes at lower prices.
Although on earlier Tyros models you could see the total memory size and the amount used (but not the brand!) of any memory module fitted from a display on the keyboard, the Tyros5 does not have this feature.
Instead you can see the size from the 'Yamaha Expansion Manager' program on a computer once you have copied an ID file from the keyboard to the program. This program is used to manage, edit, and even create expansion voices, and produce an installation file (PPI) containing your selection which is used to actually install such content on the keyboard. You can download this program from the Yamaha Support website.
Alternatively you could check visually if you turn the keyboard over and use a screwdriver to open the compartment on the bottom that contains the module.
Regarding the internal hard drive, it is very easy to install a larger one should you want to, but the factory fitted one is at least 500GB, so I can't imagine why you would want to! You can check the size of this on the keyboard without getting your toolbox out!
To do this press FUNCTION > UTILITY > Tab to MEDIA. Use the A & B buttons if necessary to select HD1, and press PROPERTY (F button).
Regards
Ian