Itching to ask...Hz limit helps frames?

jyi786

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I've been wanting to ask this question for a while.

Most LCDs are limited to refresh rates of 60Hz. Most video cards, as powerful as they are now, are able to drive fps over 100+ WITH vsync enabled (for CRTs, that is).

My question is this: If LCDs (DVI connected) are limited to 60Hz and vsync is applied, which will cap fps to 60, and video cards are capable of driving over 100fps w/vsync, would the cap free up more processing power for the video card than if it was forced to display at 100 vsync/fps?
 
No. The amount of processing does not change. VSync simply times the processed frame to be released from the back buffer in sync with the refresh rate signal of the monitor.
 
Un4given said:
No. The amount of processing does not change. VSync simply times the processed frame to be released from the back buffer in sync with the refresh rate signal of the monitor.

what he said^^
 
Will Vsync help remove ghosting on my LCD when I rotate too rapidly? If not, will a better card help? I've only got an FX5900 now, but plan to upgrade to a 6800 or 7800GS.
 
Samury said:
Will Vsync help remove ghosting on my LCD when I rotate too rapidly? If not, will a better card help? I've only got an FX5900 now, but plan to upgrade to a 6800 or 7800GS.
No, a GPU upgrade will not help with ghosting. Ghosting is normally the result of poor response time.
 
Damn. So much for wishful thinking. :rolleyes:

I don't understand. So if my video card is capable of churning out 100+fps w/vsync enabled, why do games stutter when capped at 60?
 
Samury said:
Will Vsync help remove ghosting on my LCD when I rotate too rapidly? If not, will a better card help? I've only got an FX5900 now, but plan to upgrade to a 6800 or 7800GS.

Nope, that's an issue with the panel itself. Vsync only cures tearing, and I'd highly recommend NOT using it with your 5900 as it causes framerates to dive. Triple-buffering helps somewhat.

On a side note, I hate the need for refresh rates with TFT's. The screen doesn't need to be redrawn if nothing has changed, as they don't have to keep phosphors lit like CRT's. I know it's all down to compatibility and 60Hz is due to limits of single-link DVI (meh 165MHz is not even half the bandwidth of a standard analog output), but it would be nice if a manufacturer offered up dual-link versions of TFT's which could do 120Hz or so. How pointless is a 2ms panel (bs rating of course, I note occasional ghosting on my 8ms Samsung) that can only do 60Hz :confused:
 
ajm786 said:
Damn. So much for wishful thinking. :rolleyes:

I don't understand. So if my video card is capable of churning out 100+fps w/vsync enabled, why do games stutter when capped at 60?

Because 60FPS that is the *maximum* you can attain and you may get 'stuttering' even running at this rate. The frame rendered by the card can be out of sync, as it may have processed it far too early - ie the scene movements are smaller than they would have been had the card been running at a speed which would equal 60FPS. This is why locking fps in games, like Doom3, is a good idea in my opinion.
 
ajm786 said:
I don't understand. So if my video card is capable of churning out 100+fps w/vsync enabled, why do games stutter when capped at 60?

Since it's 60 hz, you'll literally get 60 frames per second. With 60 FPS for my eyes, it is stuttery. This is the effect you will receive. To make matters worse, it seems even more stuttery when used with a LCD monitor. That's because it lags behind with response time. If you had a CRT running 60 hz vsync'd you'd get 60 fps steady as well but its response time is just so much more quicker than a LCD monitor.

To draw up something to show you what I mean:

CRT (2 ms):

|---60---|..|---60---|..|---60---|..|---60---|..|---60---|..|---60---|..|---60---|..|---60---|..|---60---|..|---60---|

LCD (16 ms):

|---60---|................|---60---|................|---60---|................|---60---|................|---60---|................

The LCD monitor lags behind the CRT greatly. This is why you feel stuttery. Even your mice may feel laggy because of the fact the LCD delays all input operations onscreen.

-J.
 
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