I bought this machine because the ram is upgradable to 512gb for use with a mapping program I use. The piece of crap ssd drive that Windows 10 was installed on and came with this machine has already bit the dust and the machine won’t even recognize the drive; after I installed all of my software. I have ordered a good ssd drive to replace it, but now I will have to start all over again installing software. Thank goodness I saved all of my data on another drive! It’s sad that someone would put such a piece of crap ssd in a great machine like an HP Z820.