LCD monitor 'refresh rates' and max frame rates.

T

theory

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Hi all,

I'm wondering how you can work out what the maximum frame rate an LCD screen can show, as I used to use a decent CRT that would display up to 160hz - so when I was playing 'first person shooters' I could quite easily see the full 100fps that I was steadily getting.

Since moving on to an LCD screen (4 or 8ms response times depending on how you measure at 60 or 70hz) I don't actually get to 'see' the same frame rate (I do get 100fps in game, but the monitor doesn't 'show' it like the CRT did)... Is the LCD's frame rate potential still linked to the refresh rate as it would be with CRT? I know that LCD's don't flicker, but how many frame sper second can they show? Also, are the response times significant to frame rate potential?

I suppose the real question is what LCD monitor could I buy to show me a genuine 100fps, or the closest to it? I know people say yuo can't differentiate anything above 60fps, but that's subjective and I disagree wholeheartedly too :)

Cheers chaps.
 
Try getting a first person shooter on a CRT at 100hz and spin the mouse fast while standing still. pay attention. Repeat the test at either 60hz/with the frame rate capped to 60, or on an LCD screen.

What LCD's will truly show 100fps? and if you believe its all of them then what is the max frame rate an LCD screen can show?

I don't really want a debate on how good (or bad) my eyes are.

Cheers.
 
indeed, any monitor can't show higher fps than its refresh rate, so on a LCD you're stuck at worst at 60fps, at best at 75. the irony : high end, high res LCD are typically the ones that don't support more than 60Hz. you can partly blame DVI's small bandwith, and 95% of people not knowing about the issue.

_xxx_ : get a nice CRT, run it at 100 or 120Hz under quake 3, vary the max framerate with the com_maxfps variable in console, and you'll see that 60fps actually looks jerky (especially in that game). such jerkyness, or should I say the discrete nature of the movement, is also visible on a LCD. somewhere around 100fps, the eye is fooled into seeing a perfectly continous movement. another, simpler test is, compare that CRT on the desktop, at 75 and 120Hz : the much higher framerate of the mouse cursor movement is very noticeable :)

I'm even thinking that our A/C current from the power outlet runs at 50Hz/60Hz (depending on your part of the world) so that electrical lights flicker at 100Hz/120Hz :) (though, the metal thread (filament?) in the bulb doesn't immediately cool down, and signal is a sine, not square)
 
Thanks Blazkowicz, the vote of confidence helps!

So do you think it is the refresh rate that is the limit on an LCD also then? It was really dissapointing for me to have to have my frame rate capped at the same point that graphics cards became so capable.

Cheers.
 
Don't play Q3, but I have yet to see any difference in games above 60Hz on any monitor. But maybe it's just me. Mouse and Windows is something completely different, that I can actually see. I wouldn't necesserily link that to refresh rates though, because "overclocking" the mouse port (PS2 back then) did the same and that had nothing to do with refresh rates.
 
_xxx_ said:
Don't play Q3, but I have yet to see any difference in games above 60Hz on any monitor. But maybe it's just me. Mouse and Windows is something completely different, that I can actually see. I wouldn't necesserily link that to refresh rates though, because "overclocking" the mouse port (PS2 back then) did the same and that had nothing to do with refresh rates.
Click to expand...

The thing is, 'overclocking' your mouse is necessary to keep up the mouse updates to match the monitor frame rate potential. So if your frame rate + refresh are at 100hz, but your mouse is only giving 60 updates then you will only see 60 changes when you swing your view around by the mouse.
 
Mouse updates have to do with how often the mouse is updated, not with much else.

I can always tell whether a screen is at 60,75 or over 80. From 80 onwards, I start having trouble telling the difference. But, ironically, as the refreshrate goes higher, the demands on the graphics cards get higher also, and that doesn't necessarily benefit the amount of times your mouse updates.

The best way to see the difference on a CRT is by moving your finger from left to right in front of the screen, and look at your finger. Do it in front of a wall, and you'll see pretty much a smooth line. Do it in front of the screen, and you will see individual fingers lining up, even at 100hz (=what I'm always running at home) and even if you don't move your finger all that fast.

With LCDs, which aren't scanlined but permanently lit, you can't tell the difference so easily - they're more like that wall, which constantly reflects light. LCDs constantly emit (let through) light. That's why they are generally also easier on the eye. If I've worked with them long enough, I start noticing slight flicker even in my 100hz CRT display, especially under natural light conditions.
 
Arwin, I totally agree with you - LCDs are better on the eye. No question there. I just want to know what the maximum frame rate potential of a 8ms/60hz LCD monitor is...

The mouse updates are relevant to the frame rate if the movement is dependant on the mouse moving, and in the test case it is dependant which is why I mentioned it. using Q3 and simply moving forward won't allow you to easily see the difference between 60 or 100fps, you really need faster movements than that which is why I suggested wiggling or spinning round.

Cheers for all the reponses so far, its interesting to see that this is clearly is misunderstood topic!
 
apoligies for what seems like spamming, but it turns out google has lead me to few pages which have clarified my beliefs, so now I'm certain that my initial thoughts were correct all along.

The potential frame rate of any monitor (be it LCD or CRT) is dependant on the refresh rate, which if set to 60hz will allow the user to see no more than 60fps.

So now my question is, what LCD panel can I buy that will give the nearest (or equal) to 100hz?

Cheers all.
 
I think I'm missing something but can't you just disable vsync and get that > 100fps?

I've played QuakeWorld quite much and after playing some games with 76fps it's easy to see if it drops to 60.
 
Although I'm not very knowledgable about this, I did a quick google and found this page which confirmed what I'd read here:

Petri Ojala said:
The TMDS signalling in the DVI interface has a maximum bandwidth of 165 Mhz, or 165 Mpixels/s. At 60 Hz this equals to a maximum resolution of 1920 x 1080 for the display over single TMDS link. Obviously not enough for a 1920 x 1200 display.

However the standard DVI interface has enough pins for two TMDS links and there are both displays and cards with a single or dual TMDS implemented (12 or 24 pins). A dual link DVI interface has double the bandwidth and therefore a maximum resolution of 2048 x 1536.
Click to expand...

I know that my viewsonic vx2025w is capped at 60 Hz @ 1680x1050, and it's my one disappointment with this monitor. However, I've seen very few LCD monitors offer 100 Hz at max resolution, at any price. Almost nobody even advertises that spec, so good luck finding one without some hands-on testing...

Edit: check out these Eizo monitors... the prices are insane, but, to the point, note that they specify both the analog and digital refresh rates. Their vertical refreshes are 85 Hz analog, and only 60 Hz digital. Almost no other manufacturers list this spec difference -- they just note the verical refresh as say "75 Hz" without specifying even what resolution that is, or whether there's a difference for the analog and digital outputs. And these are only 1280x1024 panels! -- his is still disappointing about LCDs.
 
Last edited by a moderator:
Wow, so VGA analogue is better in some ways! I didn't know that... and I'm surprised too.

Miksu, my point is that regardless of what frame rate my graphic card pumps out there is a limit to what the monitor can display so even with v-sync turned off and Q3 running at 100fps (or more) I will only see a certain amount which turns out to be entirely determined by refresh rate. :)
 
Lookup "beat frequency" to find out why you get perception of lower fps when your fps and refresh are close...
 
Dunno about monitors, but some LCD TV's like my Myrica will go up to 85 Hz, though only in low resolutions. At 1360x768 it's fixed 60 Hz.
 
Last edited by a moderator:
Mize said:
Lookup "beat frequency" to find out why you get perception of lower fps when your fps and refresh are close...
Click to expand...

Interesting stuff, makes sense. Still, not a problem I'm suffering with so all is good in the hood.

Cheers. :)
 
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