4 gig is fine (after all, X3 runs in 32bit when there is a MAX of 4 gig ram not only for X3 but for the system as well). I guess there would be limitations on how many vst's can be run concurrently, but that problem also exists on a full desktop daw running 32 bit as well. So yeah, I think 4 gig is fine.
 
I use a small unpowered dock and it runs a mouse, the ASIO USB driver (to a mixer) a program that onyl runs from a thumbdrive (copy protection reasons) and a Roland UM-1SX USB midi interface - all sweet as. It is a USB 3 port (genuine) so I imagine that is why it all runs so smoothly.
 
There is just not enough oomph in it to run a USB  Hard drive

1.  Do you have an audio interface to hook into it?
 
2.  Would a USB hard drive work if the external drive had it own power, rather than relying on the USB port?
 
A curious Bob Bone
 
 

I believe Surface Pro(s) are Intel based where as the Surface RT(s) had the ARM chip in them.
 
Regards,

Hey Bob, as I wrote I already have the audio I/F connected  
 
I have no doubt an external USB drive would be fine if it had it's own power supply. Much the same as using a powered USB hub. 
 
@ mmorgan - quite correct RT's are 100% no good for anything other than playing back music files.

Thanks - twas just curious.
 
Good luck with it - I have no clue about that whole end of things - tablets and such.
 
Bob Bone

thanks -it is working fine so far - just want to get X3 loaded up, transfer the projects over and with the the new Playlist (well the old one fixed) should be good to go!