Cactus Music
Well WASAPI turns out to be just as iffy as MME on some machines.. On my Acer 2012 Laptop it seems to be fine for playback and working with midi. I haven't tried recording yet but seems stable so far with MIDI only and VST
. 
On my Sony 2008 Laptop I managed no problem to perform the loopback test in 4 different driver modes. WASAPI came in late, It was no better than MME on that test. Only ASIO ( using my Tascam) was right on. 
On my 2012 HP Paviion i7 I could not record any audio at all, Audio engine would drop out after 1/2 second. Lots of warnings about this and that.  I tried every possible setting and each of the drivers,, gave up. Weird that the Sony worked and this one didn't. 
I waiting for Photobucket to upload my screenshot and I post a new tread regarding the loopback test and my experience so far with working in HS. 
 
All three test machines running Windows 7 64 bit.  

Windows 7 is an ancient OS. We can't guarantee great WASAPI performance there and most definitely not the kind of low latency you can get in Win10 since the OS itself has several WASAPI optimizations.

GiovanniB
...I'd like to know how many busses are allowed per project in Home Studio version...

 
Well Sonar HS6 had a limit of 16 buses. But that doesn't necessarily mean anything regarding the current version.

Home Studio Link that works for me...Features are at the very bottom...The new HS has a 64 track limit.
http://www.cakewalk.com/Products/SONAR-Home-Studio
 

I mention this in my own thread, I got to test using latest SPlat and W 10 , WASAPI was still not perfect but the offset timing was better.. But it was still late by about a 1/64 note where ASIO was bang on. 
 
And I have Windows 7 running on a few machines because W 10 does not have drivers for those. Laptops are what they are and companies never update drivers. So if you want your function keys etc to work, you cannot change the original OS.