Hi all! 
AERO on Windows 7 Windows 8 - OS-X Cocoa Frameworks
As someone already point out, AERO need to be ON to direct all graphic processing to use GPU instead on CPU.
You want the plugins and the Software instruments use all the CPU recourses not the graphic.
There are non benefits to disable AERO only the opposite.
All you see with AERO turn on is handle 100% by the GPU on the graphic card. So it can be good idea to invest in a better graphic card. DSP coding just increase every day so we will see more GPU based coding and add of more functions like plugins use the GPU processing in example Cubase in the near future.
In fact already today many 3 part manufactories base their GUI code and API calls around AERO - directed to the GPU on both Windows 7 / 8 and OS-X . Disable it you will get crashes and conflicts in Windows 7 and 8. On OS-X you can’t disable their coca framework and that is a good thing. I hope Microsoft will take that option away so can’t disable AERO in the near future.
On Windows 95, 98 and XP all Graphic behavior was to directed all to the CPU only. On XP; direct-Windows and Programs graphic processing to the GPU on the graphic card was not possible as it is today in Windows 7 and 8. There for it was recommend to use so low graphic in use as possible because it took away CPU resources for the plugins and software’s in XP. Today that is history.
About MIDI, no its not a background task either. Its a real time operation. MIDI messages are made up of 8-bit words, and are transmitted serially at a rate of 31.25 kbaud.
About Process scheduler on XP to “background task”.
That tweak has been used and abused since Matthias Carsten at RME come up with this great tweak on XP. It was meant to be used with specific RME hardware on XP platform only to provide better low latency from 23ms to 3ms.
Even Mattias Carsten that is the original founder of this tweak say as I do and Microsoft and all the tech Gurus in the world would say; that on VISTA, WINDOWS 7 and Windows 8 it should be set to PROGRAM. 
POWER Schema shall be on FULL too. Check all USB port too so isn’t set to sleep.
BIOS setting- disable all C-wait and Sleep!
UAC-User Account Control
You can go ahead and disable that in Windows 7 and 8. There were talk to take away that feature completely in Windows 8.1 update “Windows Blue”. Its no needed as in Windows 8 has another kernel core protection further down inside the core base that has stronger protections against bad code then UAC.
Windows hibernation
Windows hibernation can be a good idea to take away to free up space especially if you use SSD on /C: Windows.
Check the Internet how to do that.
Core parkingIt can be a good idea on some system to disable “core-parking” in Windows 7 and 8. This is advance operation thru reg-edit so if you have no experience you can mess up your system pretty bad and completely.
Best Regards
Freddie