So?
Today no memory exhaust, although I've worked in a 177pages pdf-file imported in 1 section on 1 ON page... but I disable wifi, is it maybe a problem with the synchronization?
It might be. If the workbook is trying to be synced up to SkyDrive with large/many files and it is taking time, it is possible that more RAM and CPU could be used, but I doubt to the extent you are seeing. It might also be a Search/Indexing thing that OneNote is trying to Index everything in the Notebooks and it is taking a large amount of resources (I really don't think OneNote was designed to handle such huge Notebooks being imported from PDF).
The most logical way of checking this is to go back tot he start and start slowing investigating from there. You have tried reinstalling OneNote multiple times (which I take it means you did an unisntall of Onenote, rebooted, redownloaded the install file and reinstalled??), so let's take that as step 1 done. The next step is to start using OneNote without any of your current Notebooks. After making sure the Notebooks are fully and completely synced, right lick them and select Close. Now open a new Notebook and start taking notes and inking. Keep your eye on the RAM and make sure it is not increasing unexpectedly.
Once you are happy that the RAM usage is normal and stable try adding your Notebooks back in, one by one and monitor. You should eventually get to a point where you can see the Notebooks that are causing issues.
Once you do get there you will need to decide what to do. It could be a PDF conversion issue, it could be a Notebook size issue, or it could be a combination of both. But you really need to work out which ones are the trouble.
And just because your Android Tablet is not having troubles (that you know of) doesn't mean that a Windows Install should be fine. They are completely different OS's and completely different OneNote apps. The features, operation and functionality between them is different.
It is also, as others have said, not a 'Surface Pro 3' thing. The Surface Pro 3 is just the hardware.