Running games in windowed mode lowers frame rate

[sparkey6]

HI, i have two monitors hooked up to my computer, which i normally watch stuff on Youtube on one monitor and play games in windowed mode on the other. The thing is even the game says its running at 60fps (using steam's built in fps/ Minecraft's debugger options) but its clearly a lot jerkier than when its full screen.
My rig is a 4790k CPU, Asus strix 970 GPU, 16gb 1866Mhz Corsair Vengence RAM and MSI gaming 9 mobo running windows 7.
my computer barely utilizes 8gb of the RAM when under load, so i don't think its a hardware problem.
Any help would be gratefully appreciated

 

[plaintuts]

What's the resolution of both monitors

 

[sparkey6]

1920x1080

 

[plaintuts]

Gpu memory is more likely the concern regarding your problem, since performance is stable when focusing on one application "full screen mode"

Also if you're using shadder mods for minecraft then that would hit gpu memory harder

 

[sparkey6]

hmm well it still does it even when i lower the minecraft settings down to minimum, even with youtube running and i disable v-sync and it caps 2000fps it still looks as if its not 60fps.
I am being exceeding picky here but it just doesn't run quite as nice when in windowed mode, and that goes for everything, even youtube videos that are at 1080p60fps, can be jerky unless i put them into full screen mode. The GPU has 4gb of VRAM, would that not be enough?

 

[plaintuts]

You're running 3840x1080 res if using extended display, windowed mode puts additional strain for also rendering other applications

So it depends on your usage if 4gb is adequate or not

 

[k1114]

It's an issue with windowed mode. Nothing you can do about it. Has nothing to do with hardware.

 

[gamerk316]

When you have an app running in exclusive fullscreen, it's the only thing the GPU is required to actually output. When you are running in non-exclusive fullscreen, EVERYTHING that is maximized is being drawn to the screen. So if you have 2-3 window apps going, that's 2-3 times the work the GPU is doing. An IE window may not seem like much, but it's gobbling up a decent portion of VRAM, and narrowing the timing window the GPU has to work on other apps.