So I have a really strange issue while running fullscreen vs windowed in all games that I own. For example I get 10-15 fps while in fullscreen mode in Fable 3 but in windowed mode still 1080 (Native) I get 40-60 fps. I am hoping someone can shed some light on this. And again this happens with all games I own.
I5-2500k stock clock speed.
Vengeance 8gb 1600
Radeon HD 5670 (2gb)
Windows 7 Ultimate
Windowed mode may increase the speed because you are using a lower resolution, getting less detail and using less pixels. It is easier on the graphics card to draw the game in a smaller square. However, full screen has the advantage of giving the whole screen to the game, letting the video card draw ONLY the game. It all depends on how the game works. If it is slow because the resolution is too high, windowed mode may help, though I'd suggest lowering the resolution in the game and running it fullscreen with the same lowered detail. If it is slow because there is too much math, like too many polygons on screen at once, then shrinking the window won't help that. Doesn't matter if it is drawing it big or small, the objects are made of the same number of polygons and each has to be calculated. Actually drawing them to the screen is the only place it may be sped up, but I would say usually full screen is faster, and definitely looks better.
Also, HD 5670 is a low end card, for 1080P gaming you must at least consider HD 6850/70, you have a beast CPU held back by that GPU.
I should revise my question. I play in fullscreen(windowed) so my res is pretty much 1080p while in windowed mode I am receiving a 500% decrease in performance when in fullscreen.... So please I'm still looking for a viable answer I am also running aero with all options so I should not be getting better fps in windowed 1080 compared to fullscreen 1080. And if windowed mode was better it should not be 500% better.
When you play windowed it's not fullscreen and it's not 1080P, and as the post above clears that you get less details & pixels make it easy for the GPU to draw than the complex of the full screen. I've searched around to come with a stable answer but I couldn't find as it's not the case in most situations, some games may incur FPS drop and some will incur FPS boost, review this thread http://gaming.stackexchange.com/questions/13066/why-is-...
It is a general concern.
When in windowed mode, the video card is busy rendering the complex graphics of the game, while the "desktop" is trying to take priority to maintain its stability. When the two coexist, the frame rate drops, as the delay between a frame an another is increased.
As a result, some games enforce that, where they detect they are in windowed mode and purposely reduce the frame rate, to allow the desktop more processing power. Of course they offer that as an option that you can turn off -- World of Warcraft is an example of that.
If your processor and graphics processor are capable of achieving high frame rate, you may not notice that performance drop, as they are faster than the delay due to processes sharing the graphics card.
This is a general answer, unless someone else has more in-depth information.
My frames are Increasing 500% in (Windowed 1920x1022) It might as well be 1080. Windowed mode selects resolution based on how big the window is and when my window is Full screen to my native monitor which is 1080p it is safe to say it is close. And my point here being that when in windowed mode the GPU has to render the 2d and 3d on the screen being the desktop in this case Windows Aero with all the Gadgets ON and Fable 3 or another game. When in full screen mode going from 1920x1022 to 1920x1080 the performance should in theory Increase or at least be very close to the same. In my case performance drops in full screen mode where windowed gets me 60 fps Full screen gets 10-15... This is not normal especially with every game I play. There is something else amiss here.
Affinity - If Fable 3, like most modern PC games, can only use a certain number (IE, 2) of your available CPU threads, and you are running it full screen, your computer will end up running at around 1/4 of it's total available speed. This is a modern gaming engineering fault, and they're only just starting to allow games 8/16 thread support. When you're in windowed mode, I suspect, your computer uses a range of threads to handle all available tasks, allowing Fable to have more of the threads available to it. (Solved by closing a lot of useless crap that you'll have running all the time. Steam, ect)
OnBoard Confusion - Depends on your config. Disable your built in GPU using BIOS, Fable could be using it as a default display adapter. I don't know why, but it's possible...
Windowed Support - Some graphics cards disable FSAA and other features while windowed mode. Even stepping down from AA16 to AA4 will give the speed difference you're talking about. Try running the game on minimum settings and recording FPS both for windowed and full screen.
Catalyst Control Center - Play around with the Application Controlled settings in the CCC - Like FSAA.
I have this problem too.
For those saying it's less pixels, i'm running the game in windowed fullscreen. Same resolution.
bmsz1234, Try changing the resolution in your game to run on a single monitor, then switch it back. I get this problem with Sleeping Dogs and it clears the issue right up.
I'm talking going from 5-6 fps @ 4908x900 to 60+fps @ 1600x900, then back to 60+fps @ 4908x900.
I can't give a good reason why this is happening, only a slight workaround.
Hope this helps.