frame rate or monitor's refresh rate!

[shopping_chang]

who can tell me what frame rate and refresh rate are!?
if the frame rate is faster than refresh rate (like 103'than 85hz),what can i see from the monitor!if there is a relationship between these two rate!tell me please!here or shopping_chang@etang.com
thanks very much!

[Novdid]

Well if your is say, 103fps and your refreshrate is 85Hz then the actual framerate you will see is 85fps, no matter if vsync is on or off, as that is how many times the screen updates per second.

But if your fps is slightly lower than 85fps say 60fps, and you have toggled vsync off, then you may encouter some artifacts like tearing while you play. But if you have vsync toggled on, then in the case I illustrated above, your actual framerate will be 42-43(85/2). That means your frame rate is in sync with your refreshrate and you won't see any tearing.

Can anyone confirm this though as I could be wrong.

[Tempest]

If it's anything like the good old DOS and Mode-X times, with vsync on you can reach a frames-per-second maximum of FPS = refresh rate.

The vertical sync pulse is being generated when the electron beam on the monitor is done drawing 1 complete refresh and returns back up (vertical retrace). This is a good time to change anything on screen, because the image on the monitor isn't being updated. Of course any more advanced graphics technique draws the new frame in another buffer while a refresh is underway, so the frame can hastily be flipped onto the screen when the next retrace occurs.

Edit: Found a good brief explanation: http://www.etestinglabs.com/benchmar...isplaysync.asp

[Joel]

I think it works out that with V-sync on your maximum frame rates is your refresh rate but if V-sync is off your frame rates will be what the card can pump out but you may experience tear because of it not being in sync with the monitor.

Joel

[TdB]

but if you get 240 framerates with a 120hz refreshrate and v-sync disabled, then you will see 240 half frames on your monitor,every second,(the upper half of the monitor will show the upper half of one frame, and the lower half of the monitor will show the lower half of the next frame. etc...).
so in reality you will get tearing(where you see the difference between the 2 frames in the middle of you screen) and 240 half frames per second.

a good rule is to enable v-sync if your framerate is higher than your refreshrate, then even the low peak fps will likely be refreshrate/2.

if your frame rate is a bit lower than your refresh rate then your avg framerate will be like refreshrate/2 and lowpeaks will be refreshrate/3, which might be too little for a fastpaced fps-shooter.

if you frame rate is very low then enable it anyway, as it won´t be the bottleneck.

if v-sync is enabled, you can make the framerate a bit more fluid(avoiding some of the lowpeaks), if you enable tripple-buffering.

i always leave v-sync enabled, because i can´t stand tearing.

[GoSharks]

You are assuming monitors draw an image frame by frame this is not true.

Monitors draw images on the screen line by line not frame by frame. A typical monitor running 1280 x 1024 at 85Hz draws a horizontal line every 11 microseconds or 91146 times per second.

Depending on the hardware and software used it is possible to start drawing lines from frame number one then update and start drawing lines from frame two and so forth on a line by line basis. Although I doubt this process is linear, it seems realistic to me that more than 85 frames per second could be interpreted and displayed and would give a better mage on the screen.


Jim Witkowski
Chief Hardware Engineer
Cornerstone / Monitorsdirect.com

[az]

IMHO, this is the problem:

more frames than the monitor can handle (full frames) are sent to it (assuming VSync is off), thus resulting in the monitor displaying frame 1 in the upper half and frame 2 in the lower half, causing tearing in a fast-moving scene.

Frames per second really only means "pictures per second" - so regardless of how much fps you graphic card is able to push to the monitor, you can never get more than the monitor's refresh rate. On the other hand, even if your monitor runs at 85Hz (or 85 "fps"), while watching a movie or playing a game with 25 fps you will of course only get 25 different pictures - but they are drawn 85 times (which you won't notice).

If you tried to run your monitor at 25 Hz, you would notice severe flickering, which is because the phosphor in the tube only glows for so long, and the image needs to be refreshed often (thus the term "refresh rate"). This only applies to tube monitors, though, with LCDs the refresh rate is more like fps, because they don't turn dark when they are not refreshed.

VSync does synchronize your fps to your screen refresh rate, to avoid the tearing effect, and should be left on, except for benchmarking purposes.

Hope I haven't made things more complicated *LOL

AZ