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The truth behind why refresh rates DO matter
Let's start with a few facts:
LCD
Response time: 4ms-30+ms
Refresh rates: 60-75hz
CRT
Response time: 2ms or less
Refresh rate: 60-160hz (depends on the quality of your monitor and resolution you're using)
Goal of this article: 1) To explain why LCD is limited in its capability at showing fast moving frames (ie. blurring and ghosting in first person shooter games) 2) Demonstrate a way people with CRT monitors can replicate LCD faults.
We'll begin with a discussion on how response times, refresh rates, and frames per second relate.
Response time is the measure of time for a pixel to change from grey to grey or black to white (depends on manufacturer's marketing department on which is the better number). In other words, response time tells you how fast the screen can show you a new image. Taking that into account, using a little math, we can calculate the maximum number of frames per second a given response time can handle. CRT monitors, for all intents and purposes, have a negligible response time, therefore allows a theoretical max fps of 500fps. This means that the response time will never be a bottleneck for the CRT monitor. LCDs on the otherhand are affected by slow response times and do play a factor in FPS output. For example, a theoretical 12ms response time is able to update the screen 83.333 times in 1 second.
Math: 1 second / .012 seconds = 83.3333 max frames per second
Refresh rate is the number of times a monitor draws or updates/refreshes the screen per second. Refresh rate is calculated in hertz. To put it simply, we can also consider refresh rate in terms of frames per second. Therefore, a refresh rate of 100hz will allow for a maximum 100 frames per second to be seen. And you can then follow a 60hz refresh rate means a maximum of 60 frames per second. The refresh rate is dictated by the type of graphics card you use but limited by the monitor in use. So if you set a refresh rate that the monitor doesn't support, the screen will go blank or you'll cause damage to the screen.
Math: 60hz = 60 max frames per second
Frames per second is the measure of frames being drawn per second. Usually this term is used in reference to video cards and games. Today's graphics cards can pump out frames per second in the hundreds for some game titles. The more frames per second potentiates a smoother appearance while playing a game. As you may have noted by now, three main factors affect the ultimate performance of how many frames you ACTUALLY observe... the response time, refresh rate, and the graphics card. So its easy to see how even though your graphics card may be reporting 300fps in a game, you're observed fps is actually a lot lower. The Observed frame per second is limited by the weakest of the three factors.
Now, we can appropriately discuss the LCD's weaknesses in fast pace games. When LCDs first came out for consumer use, it was common to see response times of 30+ms or greater... that calculates to a horrible 33.3 frames per second or less. Refresh rates were at 60hz and let's assume you had a video card that could push 100 fps with no problem. That means the response rate of the old lcds was the bottle neck. As any gamer knows, 33 frames per second is horrible to look at (for those of you who doubt this, we will replicate this on a crt monitor later in our discussion) So LCDs were not even an option for fast gaming then... but then...
Recently, the LCD market is being flooded with low reponse time monitors... 16ms, 12ms, 8ms... and yes even 4ms. Bare in mind these are all manufacturers BEST numbers, but for simplicity sake, we're gonna assume they truly perform that well.
Let's put down some figures: 16ms response time = 63 max frames per second
12ms response time = 83 max frames per second
8ms response time = 125 max frames per second
4ms response time = 250 max frames per second
Remember, we're assuming the manufacturer's have our best interest in mind and have advertised these numbers because they're true (cough, bs, cough).
If you have been following the discussion thus far, you will notice there is a HUGE discrepancy in response time and refresh rate. Yes, even though a 4ms response time will deliver a possible 250 frames per second, being capped with a refresh rate of 60 hz will limit your Observed frames per second to 60 frames per seond. Sure you're graphics card may be spittin out 250 frames/s, but the monitor is only asking for 60 of those frames... the rest of those frames your expensive graphics card spits out is wasted and ends up causing visual defects such as tearing (tearing is the phenomenon that occurs when the graphic cards out put exceeds the refresh rate of the monitor). Suggestions to fix tearing is to enable v-sync.... thereby limiting the graphics card output to match the refresh rate. In the case of a 60hz lcd, that means your monster graphics card is now outputtin 60 fps.
Bottom line is that the manufacturers have constantly improved the response times, but have not considered increasing the refresh rate. The improvement of response times serves more as a marketing tool, than actual performance gains. The 60hz refresh rate will limit any gains from response time... As far as I'm concerned, a LCD monitor that can deliver a mean 16ms response time will be able to perform optimally for a 60hz refresh rate... both will be able to deliver 60 frames per second.
At this time, some of you may be saying, "bah, refresh rate doesn't matter for lcd because there is no flickering. CRT's need higer refresh rates to counter flickering."
That is partly true... I agree. CRT's do need to achieve higer refresh rates to combat the potential flicker. CRT's phosphors light up and darken almost instantaneously... which results in flicker if the refresh rate is too low... at the same time this is CRT's advantage in response time. LCD's don't need to combat flicker, b/c it's pixels persist in an on state longer... they don't darken quickly... therefore no flicker. LCD pixels only change when told to do so. That's why using an LCD at 60hz has no flicker. LCDs are great for daily windows activities and stuff.
However when we get to fast pace games... LCDs fall apart. The limiting factor in many LCD panels today is the 60hz or 75hz refresh rate. The response time is become less and less of a factor in many cases. So many people disreguard the refresh rate, firmly believing that it just doesnt come to play in LCDs. And in most situations, that's true. But if you're a hardcore gamer, there is a difference between 60 fps, 85 fps, and 100 fps. Yes the eye can percieve greater than 30 fps... I'm not hear to argue that... you can google that yourself and find the truth. What I will do is allow some of you to replicate on a CRT how an LCD would look when playing your current games.
The setup:
Counter-strike 1.6 or CZ
Graphics card that can push an average 100 fps in CS
CRT monitor set at a refresh rate of 100 hz
Enable v-sync always on in display properties
1) Start CS
2) Go into console
3) enter the command fps_max 100 (this will set CS to allow a max of 100 fps)
4) enter the command net_graph 3 (this will allow you to see the fps)
5) Start playing, run around and move the mouse around... observer the fluidity of the movement.
6) now, enter the command fps_max 60 (this will simulate a refresh rate of 60hz of a LCD, your CRT monitor should still have a refresh rate of 100hz, meaning it will draw 100 frames per second on your screen... even if they're redundant frames due to a 60 hz cap)
7) You should immediately see a difference... it will appear blurry when you move. That's because now you're only updating at 60 frames per second, just like a LCD with 60 hz refresh rate. The 100hz of the crt monitor will ensure that there is no flickering... it essentially simulates the appearance of an LCD screens lack of flickering.
Well, that concludes this discussion. Hope this helps.
Let's start with a few facts:
LCD
Response time: 4ms-30+ms
Refresh rates: 60-75hz
CRT
Response time: 2ms or less
Refresh rate: 60-160hz (depends on the quality of your monitor and resolution you're using)
Goal of this article: 1) To explain why LCD is limited in its capability at showing fast moving frames (ie. blurring and ghosting in first person shooter games) 2) Demonstrate a way people with CRT monitors can replicate LCD faults.
We'll begin with a discussion on how response times, refresh rates, and frames per second relate.
Response time is the measure of time for a pixel to change from grey to grey or black to white (depends on manufacturer's marketing department on which is the better number). In other words, response time tells you how fast the screen can show you a new image. Taking that into account, using a little math, we can calculate the maximum number of frames per second a given response time can handle. CRT monitors, for all intents and purposes, have a negligible response time, therefore allows a theoretical max fps of 500fps. This means that the response time will never be a bottleneck for the CRT monitor. LCDs on the otherhand are affected by slow response times and do play a factor in FPS output. For example, a theoretical 12ms response time is able to update the screen 83.333 times in 1 second.
Math: 1 second / .012 seconds = 83.3333 max frames per second
Refresh rate is the number of times a monitor draws or updates/refreshes the screen per second. Refresh rate is calculated in hertz. To put it simply, we can also consider refresh rate in terms of frames per second. Therefore, a refresh rate of 100hz will allow for a maximum 100 frames per second to be seen. And you can then follow a 60hz refresh rate means a maximum of 60 frames per second. The refresh rate is dictated by the type of graphics card you use but limited by the monitor in use. So if you set a refresh rate that the monitor doesn't support, the screen will go blank or you'll cause damage to the screen.
Math: 60hz = 60 max frames per second
Frames per second is the measure of frames being drawn per second. Usually this term is used in reference to video cards and games. Today's graphics cards can pump out frames per second in the hundreds for some game titles. The more frames per second potentiates a smoother appearance while playing a game. As you may have noted by now, three main factors affect the ultimate performance of how many frames you ACTUALLY observe... the response time, refresh rate, and the graphics card. So its easy to see how even though your graphics card may be reporting 300fps in a game, you're observed fps is actually a lot lower. The Observed frame per second is limited by the weakest of the three factors.
Now, we can appropriately discuss the LCD's weaknesses in fast pace games. When LCDs first came out for consumer use, it was common to see response times of 30+ms or greater... that calculates to a horrible 33.3 frames per second or less. Refresh rates were at 60hz and let's assume you had a video card that could push 100 fps with no problem. That means the response rate of the old lcds was the bottle neck. As any gamer knows, 33 frames per second is horrible to look at (for those of you who doubt this, we will replicate this on a crt monitor later in our discussion) So LCDs were not even an option for fast gaming then... but then...
Recently, the LCD market is being flooded with low reponse time monitors... 16ms, 12ms, 8ms... and yes even 4ms. Bare in mind these are all manufacturers BEST numbers, but for simplicity sake, we're gonna assume they truly perform that well.
Let's put down some figures: 16ms response time = 63 max frames per second
12ms response time = 83 max frames per second
8ms response time = 125 max frames per second
4ms response time = 250 max frames per second
Remember, we're assuming the manufacturer's have our best interest in mind and have advertised these numbers because they're true (cough, bs, cough).
If you have been following the discussion thus far, you will notice there is a HUGE discrepancy in response time and refresh rate. Yes, even though a 4ms response time will deliver a possible 250 frames per second, being capped with a refresh rate of 60 hz will limit your Observed frames per second to 60 frames per seond. Sure you're graphics card may be spittin out 250 frames/s, but the monitor is only asking for 60 of those frames... the rest of those frames your expensive graphics card spits out is wasted and ends up causing visual defects such as tearing (tearing is the phenomenon that occurs when the graphic cards out put exceeds the refresh rate of the monitor). Suggestions to fix tearing is to enable v-sync.... thereby limiting the graphics card output to match the refresh rate. In the case of a 60hz lcd, that means your monster graphics card is now outputtin 60 fps.
Bottom line is that the manufacturers have constantly improved the response times, but have not considered increasing the refresh rate. The improvement of response times serves more as a marketing tool, than actual performance gains. The 60hz refresh rate will limit any gains from response time... As far as I'm concerned, a LCD monitor that can deliver a mean 16ms response time will be able to perform optimally for a 60hz refresh rate... both will be able to deliver 60 frames per second.
At this time, some of you may be saying, "bah, refresh rate doesn't matter for lcd because there is no flickering. CRT's need higer refresh rates to counter flickering."
That is partly true... I agree. CRT's do need to achieve higer refresh rates to combat the potential flicker. CRT's phosphors light up and darken almost instantaneously... which results in flicker if the refresh rate is too low... at the same time this is CRT's advantage in response time. LCD's don't need to combat flicker, b/c it's pixels persist in an on state longer... they don't darken quickly... therefore no flicker. LCD pixels only change when told to do so. That's why using an LCD at 60hz has no flicker. LCDs are great for daily windows activities and stuff.
However when we get to fast pace games... LCDs fall apart. The limiting factor in many LCD panels today is the 60hz or 75hz refresh rate. The response time is become less and less of a factor in many cases. So many people disreguard the refresh rate, firmly believing that it just doesnt come to play in LCDs. And in most situations, that's true. But if you're a hardcore gamer, there is a difference between 60 fps, 85 fps, and 100 fps. Yes the eye can percieve greater than 30 fps... I'm not hear to argue that... you can google that yourself and find the truth. What I will do is allow some of you to replicate on a CRT how an LCD would look when playing your current games.
The setup:
Counter-strike 1.6 or CZ
Graphics card that can push an average 100 fps in CS
CRT monitor set at a refresh rate of 100 hz
Enable v-sync always on in display properties
1) Start CS
2) Go into console
3) enter the command fps_max 100 (this will set CS to allow a max of 100 fps)
4) enter the command net_graph 3 (this will allow you to see the fps)
5) Start playing, run around and move the mouse around... observer the fluidity of the movement.
6) now, enter the command fps_max 60 (this will simulate a refresh rate of 60hz of a LCD, your CRT monitor should still have a refresh rate of 100hz, meaning it will draw 100 frames per second on your screen... even if they're redundant frames due to a 60 hz cap)
7) You should immediately see a difference... it will appear blurry when you move. That's because now you're only updating at 60 frames per second, just like a LCD with 60 hz refresh rate. The 100hz of the crt monitor will ensure that there is no flickering... it essentially simulates the appearance of an LCD screens lack of flickering.
Well, that concludes this discussion. Hope this helps.
