Help me understand vysnc in PoE (performance stuff)

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Perusoe a écrit :

VSync does not lock your framerate to your monitor's refresh rate. It caps it to your monitor's refresh rate. If the framerate in-game drops just a little, your fps will drop in multiples of your monitor's refresh rate (multiples of 60 fps for a 60 Hz refresh rate).

Currently, it is known that Vsync "Forced Off" has disadvantages. Vsync "Forced On" also has disadvantages. With today's technology, the general consensus is Vsync "Adaptive" is the best of both worlds. (Not "Adaptive (half refresh rate)")

Try opening your graphic card's Control Panel. On the Manage 3D Settings->Global Tab (or wherever you change the global settings), set the Vertical Sync to "Adaptive" and see if that helps.

Note: Any global settings in the video card's Control Panel should override the game's video settings. Even so, I have my video card's global Vsync set to "Adaptive". In PoE, I have Vsync on the Graphics Tab of the Options Panel unchecked.

No, vsync definitely locks your frame rate to the refresh rate of your display. The games rendering code constantly checks the display for it to report vblank (When the display finishes drawing a frame) before proceeding to render the next frame of video.

Vsync makes use of 2 buffers, Buffer One is used for sending data to the display (It is locked during this operation) and Buffer Two is for rendering the next frame. So in essence the game is rendering one frame in advance of vblank and storing it for the moment vblank arrives at which point it will swap it in to the 1st Buffer for display. The game will render a frame and wait for the display to finish rendering the current frame (Display reports vblank when finished) before submitting the new frame to the display.

A simple frame rate limiter will not fix screen tearing as it can very easily go out of sync with your display. This is because displays don't operate at precisely 60hz and a frame rate limiter doesn't give a hoot about vblank. So the computer can send the next frame of footage before the display has finished displaying the current frame of footage, causing it to start displaying the next frame of footage without completing the existing frame of footage. (You end up with half a frame of previous footage and half a frame of current footage etc.)

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Nicholas_Steel a écrit :

No, vsync definitely locks your frame rate to the refresh rate of your display.

Source: HARDOCP - NVIDIA Adaptive VSync Technology Review

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Perusoe a écrit :

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Nicholas_Steel a écrit :

No, vsync definitely locks your frame rate to the refresh rate of your display.

Source: HARDOCP - NVIDIA Adaptive VSync Technology Review

That's not vsync. That's a modified, propriety version of vsync.

Edit: Also a very simplified/layman's explanation of vsync that glosses over the technical mechanics.

I'm still unclear on my original question. If I disable vsync (no FPS limiter), my framerates never drop below 100, and usually stay closer to 200 fps. If I turn on vsync, I frequently get drops to 15-20 in certain areas of the game (Imperial Gardens, Dominus). However, with vsync off, in these very areas I see no fps dps that go below 60.

What is the explanation for this?

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Mivo a écrit :

I'm still unclear on my original question. If I disable vsync (no FPS limiter), my framerates never drop below 100, and usually stay closer to 200 fps. If I turn on vsync, I frequently get drops to 15-20 in certain areas of the game (Imperial Gardens, Dominus). However, with vsync off, in these very areas I see no fps dps that go below 60.

What is the explanation for this?

Unsure I'm afraid, perhaps GGG's implementation of vsync simply isn't up to scratch or your computer BIOS/Windows has power saving settings enabled that interfere with it.

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Mivo a écrit :

I'm still unclear on my original question. If I disable vsync (no FPS limiter), my framerates never drop below 100, and usually stay closer to 200 fps. If I turn on vsync, I frequently get drops to 15-20 in certain areas of the game (Imperial Gardens, Dominus). However, with vsync off, in these very areas I see no fps dps that go below 60.

What is the explanation for this?

Its possible you have a temporary drop in performance to that point, and then your video drivers decide thats it is better to leave it there for a steady frame rate instead of it constantly hopping around. Thats just a guess, and digging around in your video drivers may bring you more information.

In your case, a frame rate limiter would be your best option over vsync. Just cap that fucker at 60 and call it good. Then you wont overheat, and you will still have good fps.

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tramshed a écrit :

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Mivo a écrit :

I'm still unclear on my original question. If I disable vsync (no FPS limiter), my framerates never drop below 100, and usually stay closer to 200 fps. If I turn on vsync, I frequently get drops to 15-20 in certain areas of the game (Imperial Gardens, Dominus). However, with vsync off, in these very areas I see no fps dps that go below 60.

What is the explanation for this?

Its possible you have a temporary drop in performance to that point, and then your video drivers decide thats it is better to leave it there for a steady frame rate instead of it constantly hopping around. Thats just a guess, and digging around in your video drivers may bring you more information.

Yeah from the sounds of it your performance is dropping for split seconds every so often.

Too short a time period for your monitoring software to detect/display (It isn't refreshing the FPS indicator 1,000 times a second, instead it refreshes it once every whole second for example, which leaves the door open for tiny hiccups to go undetected by you)