Actually it will buy you performance increases across the board if you look at the benchmarks. I do notice it. Whether they are significant enough to upgrade is the debate...

CakeAlexS
Actually it will buy you performance increases across the board if you look at the benchmarks. I do notice it. Whether they are significant enough to upgrade is the debate...

Don't need to read benchmarks...   
I've compared performance on exact hardware configurations.
Load a (substantial) finished project on the exact same hardware (one load of Win7x64 and the other of Win8.1x64).
What you'll find is that the CPU use is slightly higher under Win8.1x64.
On current generation hardware, the performance difference is minimal.

I was really scpetikal about win 8.1 but :
 
1) this makes full sens with touch screen ability : a pure joy , can't go back 
 
2) The dpc latency (use matency mon) was surpisingly better than win 7 to my surprise !!! They really did a great job on it 
 
so my advise , take what you want , but 8.1 is really great and better in a lot of areas , and at least as good in overs...

Jim Roseberry

Don't need to read benchmarks...   
I've compared performance on exact hardware configurations.
Load a (substantial) finished project on the exact same hardware (one load of Win7x64 and the other of Win8.1x64).
What you'll find is that the CPU use is slightly higher under Win8.1x64.
On current generation hardware, the performance difference is minimal.

Well I could go on forever but that is not my experience or most benchmarks. I don't think running a project is particularly accurate either as third party code and caching comes into play (inc drivers), a more rounded test a number of projects from simple to complex several times. One thing is that Win 8.1 does need some optimization esp stopping services and processes that are unneeded in a DAW environment (and latest updates). Same as 7. We probably agree both however there isn't that much difference.

There are reports that the new Windows 10 will be a free upgrade for Windows 8.1 users. 
 
I have a dual boot system, Win 7 64 bit and Win 8.1 64 bit.  Both work equally well with Sonar X3 for me.  My backup system is Windows 8.1 64 bit.   Back in January of this year, the motherboard in my main system (the dual boot) developed problems and was sent back for warranty repair (they actually replaced it).  While that PC was down, I used my backup system and didn't "miss a lick" with the Win 8.1 and Sonar.
 
I have "Start8" installed on my Win 8 systems.  They boot up to a desktop that looks and works exactly like Windows 7 (I still have the Metro if I want to use that).

thanks for the input everyone

One comment Alex mentioned is very important - drivers. Some hardware did indeed stop driver updates with Win7, so if you go the 8.1 route, be sure to check Microsoft's hardware compatibility site.

CakeAlexS
Well I could go on forever but that is not my experience or most benchmarks. I don't think running a project is particularly accurate either as third party code and caching comes into play (inc drivers), a more rounded test a number of projects from simple to complex several times. One thing is that Win 8.1 does need some optimization esp stopping services and processes that are unneeded in a DAW environment (and latest updates). Same as 7. We probably agree both however there isn't that much difference.

Alex, I think you know my background.
I've been building DAWs professionally for the better part of 20 years.  
My testing isn't limited to a single machine/project.
There's no set of benchmarks that better portray DAW performance than running actual audio projects.
 
If anyone buys Win8.1x64 expecting major performance gains (over running Win7x64 on the exact same hardware), they will be disappointed.
 
Want some easy to test proof?

• Setup a current generation build with both Win7x64 and Win8.1x64.
• Bring each OS up-to-the-minute with updates.
• Optimize each OS for maximum DAW performance.
• Make sure to use the exact same audio interface.
• Load Sonar X3.  
• For easy comparison with other folks, load some of the (finished) demo projects that were included with Sonar over the last several years.
• Start each project and monitor CPU use via Task Manager.

 
That said, Win8.1x64 is a fine OS.  I've been running it for a long time.
There's absolutely nothing wrong with Win8.1x64 as a DAW platform.
 

mettelus
One comment Alex mentioned is very important - drivers. Some hardware did indeed stop driver updates with Win7, so if you go the 8.1 route, be sure to check Microsoft's hardware compatibility site.

This is the primary reason I have not upgraded. I have had issues getting proper updates of drivers as it is for a couple items .

I recalled vaguely the blog post in #3 of this thread, but then it occurred to me that the benchmarks done were with X1.
 
FWIW, I wouldn't go toe-to-toe with Jim about system performance, is best to just sit back and read his posts.