What processor and ram levels are you running? The Surface 4 and Surface Pro vary widely in configurations. I’m doubtful that the core M processors with only 4gb ram would cut it…
Dual core Skylake i7 (6600U) with 16 GB Ram and 512 GB SSD. Runs Dorico pretty well with the built-in audio and ASIO4ALL. It handles most music apps I carry with me.
Hi Paul:
I noticed that you are using Dorico on the Surface Pro 4. I have a Surface Pro 4 as well, but haven’t used Dorico with that yet. How is it working out for you? I could try it myself, but before moving the Dorico license to a dongle, I’d like to hear about your experience.
Thanks!
Peter
My wife has a Surface Pro 4, Dorico works perfectly on it. High DPI scaling is nice (because the higher resolution display allows to set a scaling factor of 200 % unlike my own Surface Pro 3 which is problematic because of a 150 % scaling factor).
I don’t use the touch capabilities much in Dorico - keyboard combinations/MIDI input are much easier.
The only drawback is that I always need a USB hub for the dongle and the MIDI controller because there is only one USB port.
I’ve tried NotateMeNow and Symphony Pro, and all I can say is that it is quicker for me to press one (or two) buttons than to draw compound shapes of circles and lines.
As opposed to the Dorico or NotePerformer fan clubs? Would the world be a “better” place if we all drove the same cars and used the same computers? 
Buy a Surface Pro !
Yes, the Surface Pro is probably your best bet if you want a laptop that can handle Dorico as well as other applications designed to be used with a touch screen. However, you should consider its usability carefully if you want the touch screen mostly for working with Dorico. Because Dorico is not designed with touch screens in mind, note entry using the Surface Pen would involve tapping the screen at the appropriate place in the same way you would use a mouse or touchpad to do the same thing. I understand most Surface Pro owners who use Dorico prefer to instead use the built-in keyboard just like they would with other laptops. This is NOT a criticism or design weakness of the Surface Pro but simply reflects the reality that Dorico is not designed with touch screens in mind as is StaffPad, for example. However, I have heard positive reports about the Surface Pro and would seriously consider one myself if, in addition to Dorico, I wanted to use Windows 10 applications designed for use with a touch screen.
Your only way around this is to run dorico on a mac and use one of the wifi dongles that allow you to use the ipad as a monitor.
re: the wireless iPad Pro touchscreen Mac Mini Setup! - YouTube
There are a few topics intermixed here: for starters, whether you can run Dorico on a tablet (yes, if you have a Surface), whether you can run Dorico on an iPad (no, because iOS is a different operating system from Mac OSX; the Dorico team has its hands full implementing a full feature suite for its target operating systems, so it’s not realistic to expect them to start an iOS re-imagination of relatively nascent software).
Implied by this discussion is a question of whether any notation software can be well run on any tablet. Most handwriting-recognition efforts seem to be closer to proof of concept than useful tool, where notation is concerned. Mouse-and-keyboard paradigms don’t adapt well to a tablet, and drag-and-drop is an agonizingly clumsy way to input notation.
The dream I think everyone has is a tablet that reads handwritten notation input with a stylus, and which allows ergonomic editing via the same means. I wouldn’t be surprised if Team Dorico solves this problem one day, but I’d expect it to happen in a decade rather than a year.
Seems to me the best use of an iPad for Dorico is as an input device that replaces the qwerty keyboard, midi keyboard, and on-screen toolboxes in the desktop software.
Am I the only one that finds the use of a qwerty keyboard for music notation clumsy and archaic? I don’t need handwriting recognition (it’s not as fast or accurate as keyboard shortcuts), yet memorizing keyboard shortcuts is daunting and unintuitive. Even after long stretches of use, I still sometimes forget which number corresponds to which rhythmic value, or whether I should press cmd, ctrl, or opt to call up a function.
I would LOVE to have a screen on my iPad where I could touch the various symbols, articulations, rhythms, pitches, toolbox items, menu items, etc. A portion of the iPad screen could contain a midi keyboard or a staff for note input. THAT would be a real workflow improvement for me, and would be so much more intuitive. No need for handwriting recognition or an iPad version of Dorico.
John, try this thread for starters: Macro keypad? - Dorico - Steinberg Forums
Metagrid seems to be the go-to iPad app for these purposes. I don’t know whether it can replace a midi keyboard but it’ll certainly cover any keyboard shortcuts you can think of (or manually assign).