Tried posting this yesterday, but something got flubbed so I'm re-writing it. Hopefully it doesn't show back up randomly
 
So, I'm working on an entire new DAW build, and my 120gb SSD is coming in the mail tomorrow, so 
I also broke my Windows 7 install trying to partition the drive - Boot manager is missing now - so I sort of HAVE to install Windows 10, it seems. Good thing I bought that too! So my questions are as follows:
 
1) I know I should put my OS and most-used applications onto the SSD. But is there any point in installing my VST's and sample libraries onto it as well? I figured it'd be nice for Cakewalk to be able to access those files quickly, but I'm not sure if "that's how it works".
2) Has anyone had any success installing an app on one OS and running them from a shared Program Files folder on another OS (Win7 and 10, I mean - not OSX and Ubuntu, f.ex.)? I was thinking it could save me some installation space to just allow each OS to install the components it needs to run each application, for itself, and then share the rest of the files between the two.
Or I could just leave Windows 7 where it is, uninstall the old software from the old OS, and reinstall everything from the ground up in the new OS (might go in this direction, as I won't be going back to Windows 7 for any reason anyway. On top of that, the applications I want to "dual-execute" are mostly large ones that can safely be installed on and used from just the Windows 10 side anyway). But the app itself is pretty small - is it possible to share all the Cakewalk Content from the previous OS? That'd save about 10gb + everything that came with X2. How do?
 
 
Whaddya think? 
 
If I come up with any more questions, I'll make 'em known here. Thanks, those of you who've helped me through the process thus far :)

Update:
I'm still talking myself through the process. Here's my revised planning for "storage blocking", as I call it:
 
120GB SSD

• OS
• Frequently-used applications
• Should I put VST instruments and sound/sample libraries on here? They were previously installed on my 2TB drive mostly, but that was noted for being seemingly quite slow to loading in samples
• This'll be backed up onto another 160gb portable HDD

750GB HDD

• Partition 1: 250gb - Cakewalk Projects (I'm using about 160gb at the moment)
• Partition 2:~500gb - Old Windows install, lesser-used application

2TB ext. HDD

• Partitions 1 & 2: 250/500gb - Backup/Mirror of 750gb drive's 1 & 2 partitions
• Partition 3: ~1.3tb - Mass Media/random, extraneous file storage

 
Then, sometime later I'll buy another 2tb internal HDD and switch the current out to use as a backup.
 
Any answers yet, guys? I'm going to just migrate the Cakewalk Content onto another drive to save space, and then lump my personal collection of files in with them so that they can all be easily accessed from one location.
I'm just really curious as to good, effective ways to go about this.

I put my Windows 10 OS, Sonar and all my other apps, and my VST plugins on my C: drive (SSD).  Sonar launches in a few seconds, and so do many projects without large sample libraries attached to the plugins.
 
I put my Cakewalk Content path, Command Center installer path, and VST sample libraries on my D: drive (HDD).  Many VST installers will offer a choice of separate paths for installing the plugin itself and the sample content.  I think my next upgrade will be to get a big fat SSD for my D: drive. 
 
Not sure why you want to keep your old Windows install around on an internal hard drive, unless you intend to dual boot.  I wouldn't attempt to share anything but document folders between two different Windows OS.
 
What I usually do when I migrate to a new system or OS is to make a complete backup of the old system onto an external drive.  Then use that to restore any documents, projects, pictures, emails, bookmarks, etc. that I want on the new system.  I keep the archived backup around in case I ever discover that I forgot to copy something, so I always have it.
 
But as far as applications go, I always install them clean and fresh, on the new system.  Look at it this way, you might have to re-customize some config settings, but at least you aren't bringing any old bugs along on the trip! 
 
I think it sounds like you are well on your way to success.  Good luck with the build!

A few applications might work from a shared program files directory, or even any other directory. But if an application expects to see stuff it needs in the registry, program data directory or temp directories then those are tied to their "own" Windows installation.

Accessing data between multi-booting copies of Windows is as straightforward as sorting out permissions so the various installations have the required access to the files. Sharing things like the registry or system directories and contents is something else.

So if dual-booting it's good practice to install applications that are needed in both boot environments so each boot environment has its own copy.

I forgot to mention. If you're using a small SSD for the OS and applications, Windows junction points can be very useful in letting you move things like the contents of user directories to other drives while Windows still 'thinks' they are in the original, OS required location.

Also useful for shifting things like sample libraries that the sampler expects to find on the C drive and doesn't itself let you choose alternative installation locations.

How big’s your SSD, abacab? I’ve got probably no more than 20gb worth of VST’s and samples. I *feel like* I’d end up on the safe side of the gamble if I put that stuff on the SSD (120gb, leaving ~20gb free). In some cases I use a lot of samples, and I’m a big user of sample-based VST as you’ve probably seen before, so it’d be cool if they were quickly accessible for SONAR. Plus, it’d make use of other free space on the SSD, because I’m going to install general applications that I only open once every 2-and-a-half blue moons onto my 750gb hdd (unless I DO end up with a load of free space on the C drive).
 
I was being dumb a couple days ago trying to partition the 750gb OS drive and managed to corrupt the bootmgr in some way or another, so I can’t boot into Windows 7 anymore anyway. I’d already rescued all the files I wanted, gotten rid of stuff I don’t, and deactivated what I needed to, and even made a backup image onto one external HDD; hopefully I’m safe (as far as the old install goes) if I go ahead and format the drive and partition it as I meant to, using it for project files and applications. Maybe a bit of media storage as well, we’ll see.
 
Just *really* hoping on my SSD arriving tonight so I can finally knock it out and call it a day on all this waiting! 

tlw
I forgot to mention. If you're using a small SSD for the OS and applications, Windows junction points can be very useful in letting you move things like the contents of user directories to other drives while Windows still 'thinks' they are in the original, OS required location.

Also useful for shifting things like sample libraries that the sampler expects to find on the C drive and doesn't itself let you choose alternative installation locations.

Hey tlw,
I actually managed to break Windows 7 so I can't use it. I guess I *had* been considering dual-booting, but I also knew I wasn't going to seriously open Windows 7 anymore with any thoughts other than to retrieve something I may've forgotten. It probably would've been cool to try though.

davdud101
How big’s your SSD, abacab? I’ve got probably no more than 20gb worth of VST’s and samples. I *feel like* I’d end up on the safe side of the gamble if I put that stuff on the SSD (120gb, leaving ~20gb free). In some cases I use a lot of samples, and I’m a big user of sample-based VST as you’ve probably seen before, so it’d be cool if they were quickly accessible for SONAR. Plus, it’d make use of other free space on the SSD, because I’m going to install general applications that I only open once every 2-and-a-half blue moons onto my 750gb hdd (unless I DO end up with a load of free space on the C drive).

I am running a Samsung EVO 850 SSD, 250GB.  Lots of room compared to my old 80 GB boot drive, but I am using about 160GB right now.  I have a bunch of demo software I am trying out right not, but lately it has been averaging about 130GB in use.
 
Another cool thing about having the SSD is using it as your default downloads path. It make the unzipping and install of large programs a snap! 
 
But some samplers have huge install footprints because you will end up with three copies temporarily.  When you unzip an installer, it has to expand the files into a regular folder so that you can run the installer.  Then the installer installs the application to the destination folders.  So installing a 40GB sampler could take up to 120GB of disk space temporarily, until you archive the installer offline.  Something to think about ... but you could always move or delete the zip file once you have it unzipped to cut down on the space needed.

abacab
 
I am running a Samsung EVO 850 SSD, 250GB.  Lots of room compared to my old 80 GB boot drive, but I am using about 160GB right now.  I have a bunch of demo software I am trying out right not, but lately it has been averaging about 130GB in use.
 
Another cool thing about having the SSD is using it as your default downloads path. It make the unzipping and install of large programs a snap! 
 
But some samplers have huge install footprints because you will end up with three copies temporarily.  When you unzip an installer, it has to expand the files into a regular folder so that you can run the installer.  Then the installer installs the application to the destination folders.  So installing a 40GB sampler could take up to 120GB of disk space temporarily, until you archive the installer offline.  Something to think about ... but you could always move or delete the zip file once you have it unzipped to cut down on the space needed.

 
That's cool! Though I'm not one normally plagued by slow installation speeds (and I'd better not start using the SSD for it - I get the impression I'd end up REALLY missing it if I ever had to switch back to using HDDs for the same kinda task somewhere down the road). But there is always the option of having the default Downloads folder be on an HDD, and just install to a proper folder on the SSD, right? I'd think so, so that'll make this pretty viable.

i did basically the same thing - 250GB SSD for OS and programs, 500GB SSD for active projects and samples, 2TB HDD for archive, and 2TB ext USB drive for backups