Hz vs FPS what's the difference
Not being an advanced 3d user could someone explain to me the difference between Hz(refresh rate)and FPS(frames per second)?
After extensive reading on these forums, it appears that many posters are using the 2 terms as one and the same.
I understand how low FPS impacts the playability of a videogame, but what effect does refresh rate have on FPS?
Not being an advanced 3d user could someone explain to me the difference between Hz(refresh rate)and FPS(frames per second)?

After extensive reading on these forums, it appears that many posters are using the 2 terms as one and the same.

I understand how low FPS impacts the playability of a videogame, but what effect does refresh rate have on FPS?

#1
Posted 02/12/2011 12:50 PM   
[quote name='churnobull' date='12 February 2011 - 07:50 AM' timestamp='1297515007' post='1192616']
Not being an advanced 3d user could someone explain to me the difference between Hz(refresh rate)and FPS(frames per second)?
After extensive reading on these forums, it appears that many posters are using the 2 terms as one and the same.
I understand how low FPS impacts the playability of a videogame, but what effect does refresh rate have on FPS?
[/quote]

FPS is a reference of quantity, Hertz is a measure of speed. If a computer can pump out 120 FPS on a game, but the monitor refreshes at 60hz, anything over 60 FPS is a waste of resources. Turn your graphics up. 3D requires a refresh rate of 120hz because it renders everything twice, and splits the difference to make it 3D
[quote name='churnobull' date='12 February 2011 - 07:50 AM' timestamp='1297515007' post='1192616']

Not being an advanced 3d user could someone explain to me the difference between Hz(refresh rate)and FPS(frames per second)?

After extensive reading on these forums, it appears that many posters are using the 2 terms as one and the same.

I understand how low FPS impacts the playability of a videogame, but what effect does refresh rate have on FPS?





FPS is a reference of quantity, Hertz is a measure of speed. If a computer can pump out 120 FPS on a game, but the monitor refreshes at 60hz, anything over 60 FPS is a waste of resources. Turn your graphics up. 3D requires a refresh rate of 120hz because it renders everything twice, and splits the difference to make it 3D
you necessarily have the hertz but not necessarily the fps
you necessarily have the hertz but not necessarily the fps

#3
Posted 02/12/2011 03:00 PM   
Hz - how many times your screen draws per second. This is purely a function of your monitor. It does get a little confusing now with S3D because we say the monitor drops from 120Hz (the whole screen draws 120 times per second) down to 60Hz when it still is drawing the screen 120 times per second, it's just that it is doing it 60 times per second for each eye. 60Hz is 'magical' because it is roughly the point where the brain no longer sees the blinking.

FPS - how many times per second that your computer is building a frame (a picture for your monitor to draw). Changing in-game settings like anti-aliasing will lower your FPS because your video card will have to do more to kick out every frame. Again, S3D makes this a little strange because now you need two pictures to make a single frame.

Verticle Sync - if your FPS gets higher than your Hz, you get a "tearing" effect because your computer goes and changes the picture that is supposed to be drawn while the monitor is in the middle of drawing the old picture. Verticle sync caps FPS at your monitor's refresh rate to fix this problem.

Different types of games need higher FPS. If you've got a game with hair-trigger timing like a first/third person shooter then having 40+ FPS helps quite a bit. The less twitch-based games need less. If FPS drops down to around 10, it starts to get difficult to simply select menu options.

(So why is it that, historically, the first person shooters have had the most advanced graphics when those are the games where you are most likely to want to dial down the graphics settings!? The best graphics should be in turn-based games like Civilization and Wizardry!)
Hz - how many times your screen draws per second. This is purely a function of your monitor. It does get a little confusing now with S3D because we say the monitor drops from 120Hz (the whole screen draws 120 times per second) down to 60Hz when it still is drawing the screen 120 times per second, it's just that it is doing it 60 times per second for each eye. 60Hz is 'magical' because it is roughly the point where the brain no longer sees the blinking.



FPS - how many times per second that your computer is building a frame (a picture for your monitor to draw). Changing in-game settings like anti-aliasing will lower your FPS because your video card will have to do more to kick out every frame. Again, S3D makes this a little strange because now you need two pictures to make a single frame.



Verticle Sync - if your FPS gets higher than your Hz, you get a "tearing" effect because your computer goes and changes the picture that is supposed to be drawn while the monitor is in the middle of drawing the old picture. Verticle sync caps FPS at your monitor's refresh rate to fix this problem.



Different types of games need higher FPS. If you've got a game with hair-trigger timing like a first/third person shooter then having 40+ FPS helps quite a bit. The less twitch-based games need less. If FPS drops down to around 10, it starts to get difficult to simply select menu options.



(So why is it that, historically, the first person shooters have had the most advanced graphics when those are the games where you are most likely to want to dial down the graphics settings!? The best graphics should be in turn-based games like Civilization and Wizardry!)

#4
Posted 02/12/2011 03:02 PM   
Zloth pretty much nailed it. I'll just add that with 3D, you pretty much have to use Vsync. Most people don't use VSync if they don't use 3D to minimize input lag.

When you use VSync it is very important to maintain your fps above your monitor refresh rate. This can be tough to do with a refresh rate of 120Hz. If your frame output drops even a little below 120 fps (lets say 110 fps), then when the monitor is ready for the next frame it will not be quite ready. With VSync on there is no waiting for the next frame to be done, it just renders the old frame a second time. This effectively drops your fps in half if it is consistantly below your refresh rate. In other words, if your PC can generate 110 fps and you are using VSync on a 120Hz monitor, you will see about 60fps. For some most games 60fps is acceptable, but it will add noticable input lag. I was going to say that 60fps is not acceptable for fast paced multiplayer games, but honestly I have yet to find a multiplayer game you can play as well in 3D. Even at 120+fps there is an input lag handicap that is tough to overcome. Still, I generally do what I can with resolution, quality settings, and hardware to keep my minimum fps above my monitor frequency. I gives a noticably better experience than slightly higher settings and laggy play. YMMV.
Zloth pretty much nailed it. I'll just add that with 3D, you pretty much have to use Vsync. Most people don't use VSync if they don't use 3D to minimize input lag.



When you use VSync it is very important to maintain your fps above your monitor refresh rate. This can be tough to do with a refresh rate of 120Hz. If your frame output drops even a little below 120 fps (lets say 110 fps), then when the monitor is ready for the next frame it will not be quite ready. With VSync on there is no waiting for the next frame to be done, it just renders the old frame a second time. This effectively drops your fps in half if it is consistantly below your refresh rate. In other words, if your PC can generate 110 fps and you are using VSync on a 120Hz monitor, you will see about 60fps. For some most games 60fps is acceptable, but it will add noticable input lag. I was going to say that 60fps is not acceptable for fast paced multiplayer games, but honestly I have yet to find a multiplayer game you can play as well in 3D. Even at 120+fps there is an input lag handicap that is tough to overcome. Still, I generally do what I can with resolution, quality settings, and hardware to keep my minimum fps above my monitor frequency. I gives a noticably better experience than slightly higher settings and laggy play. YMMV.

#5
Posted 02/12/2011 07:30 PM   
Las week I´m playing using 100hz and not 120, and I feel it is better. The bad is that I have a little flickering, but much more brightness and seem to be a little less ghosting when the monitor is hot. Also most games seem to be played smooth enough using 100hz. I´m using samsung 2233rz. Sport games like fifa 11 are really better with this more bright addon.
Las week I´m playing using 100hz and not 120, and I feel it is better. The bad is that I have a little flickering, but much more brightness and seem to be a little less ghosting when the monitor is hot. Also most games seem to be played smooth enough using 100hz. I´m using samsung 2233rz. Sport games like fifa 11 are really better with this more bright addon.

Windows 7 64bits (SSD OCZ-Vertez2 128Gb) - MSI Nvidia GTX 1060 TI - Mobo ASUS P6X58D-E - CPU Intel Xeon X5670 @4000MHz (20.0[12-25]x200MHz)- RAM 16 Gb DDR3 1600 - Monitor Dell S2716DG (2560x1440 @144Hz) - Labrador dog (cinnamon edition)

#6
Posted 02/12/2011 09:31 PM   
I didn't know you could adjust the refresh rate of a LCD monitor. I use 110Hz on my CRT, which works fine. Years ago there was talk that at 120Hz and above the LCD shutter glasses would not be as effective at blanking alternate eyes, leading to more light bleeding through or ghosting. I have never seen that objectively demonstrated though.
I didn't know you could adjust the refresh rate of a LCD monitor. I use 110Hz on my CRT, which works fine. Years ago there was talk that at 120Hz and above the LCD shutter glasses would not be as effective at blanking alternate eyes, leading to more light bleeding through or ghosting. I have never seen that objectively demonstrated though.

#7
Posted 02/12/2011 10:38 PM   
In my experience using a CRT monitor I had A LOT of ghosting, using a Samsung CRT monitor at 120hz (I do not remember the model, but lastest models with flat screen and with magicbright option).

Using samsung 2233RZ at 1680x1050@100hz I notice less ghosting in top and down areas of the screen. Also the screen is not as hot as with 120hz. Colors are more vivid because it is brighter. Flickering is the problem, but I think it worth to live with it.
In my experience using a CRT monitor I had A LOT of ghosting, using a Samsung CRT monitor at 120hz (I do not remember the model, but lastest models with flat screen and with magicbright option).



Using samsung 2233RZ at 1680x1050@100hz I notice less ghosting in top and down areas of the screen. Also the screen is not as hot as with 120hz. Colors are more vivid because it is brighter. Flickering is the problem, but I think it worth to live with it.

Windows 7 64bits (SSD OCZ-Vertez2 128Gb) - MSI Nvidia GTX 1060 TI - Mobo ASUS P6X58D-E - CPU Intel Xeon X5670 @4000MHz (20.0[12-25]x200MHz)- RAM 16 Gb DDR3 1600 - Monitor Dell S2716DG (2560x1440 @144Hz) - Labrador dog (cinnamon edition)

#8
Posted 02/14/2011 04:28 AM   
There was significant ghosting with my old Revelators, but the 3D Vision glasses seem to work better, with little to no ghosting at all on my CRT. There is a slight flicker in TF2, but none at all in Fallout or Metro. One of these days I will try going from 1600x1000 @ 110 to 1280x800 @ 138 and see if that effects the smoothness. I'd buy a new LCD tomorrow if I know of one that would look better.
There was significant ghosting with my old Revelators, but the 3D Vision glasses seem to work better, with little to no ghosting at all on my CRT. There is a slight flicker in TF2, but none at all in Fallout or Metro. One of these days I will try going from 1600x1000 @ 110 to 1280x800 @ 138 and see if that effects the smoothness. I'd buy a new LCD tomorrow if I know of one that would look better.

#9
Posted 02/14/2011 05:26 AM   
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