System Survey, What kind of a system do you have?

I have it set at 60 hz because I have no idea what that means, so thats what I left it at. Feel free to educate me though.

I dunno... I ran the Lost Coast / Source stress test thing and thats the number it gave me at the end. I dont have Vsync enabled... Im guessing thats why its so high?

Nice system mate

Gather ye round, children, and I will enlighten you.

Ok, first of all, you either have an LCD monitor (flat) or a CRT monitor (boxy). The major difference in the way they display images is that, with a crt monitor, the image on screen flashes on and off, on and off many times a second. If you have your monitor set to 60Hz, the image will flash on and off 60 times in a second (60 images, 60 black screens). Unfortunately, this flicker is very noticeable at low refresh rates, up to about 60-70 Hz, depending on the individual. Some people even claim to be able to see this flicker all the way up to 80Hz. This can cause headaches, nausea, etc (My old CRT gave me headaches when it was beginning to break down), and even if you can't detect this flashing of the screen, your brain sure can, and everything you look at will look slightly "off", though you couldn't put your finger on what exactly.

NOW THEN on to LCD - LCD images don't flash on and off, but any given pixel on the screen stays there untill a command to change comes. They are slightly slower responding than CRT monitors, and so may produce a very slight blurring effect, depending on things like response time of the monitor, which isn't important right now. So you may well be thinking, if LCD monitors don't have a refresh rate (they don't go on-off-on-off) then what difference does the refresh setting make?
LCDs are made to operate optimally at a certain refresh rate, so changing it down from, say, 75Hz to 60Hz messes the timing of the internal workings very slightly, and so slows down the monitor.

The moral of the story is set your desktop refresh rate to as high as your monitor allows; this will give less flicker or less blurring, depending on the screen type.


VSync

VSync stands for Vertical Synchronization. Bacon right - it limits the amount of frames your graphics card churns out every second.
"ZOMG Why wood i limit da FPS of my gAimz?? noob"
Imagine your monitor is running at, say, 1 Hz (FPS)
Imagine also your graphics card is painstakingly drawing screens at 2 FPS
This is fine - your graphics card makes a frame, monitor draws it, graphics card makes a frame, monitor is not ready, graphics card makes another frame, monitor draws etc. For every second your monitor draws a frame, and every second your graphics card makes two, which means that half the frames are wasted. This is ok though, because it still seems like a constant and steady 1 FPS to the user.

Now imagine your brand new screen is running at 3 Hz (FPS)
Now, your old card struggles out 2 FPS
Your angry monitor is demanding a new frame every time it refreshes, so lets see how this works:
1) Monitor asks for the 1st frame, graphics card only has 2/3 frame done, so monitor shows blank screen
2) Monitor again asks for 1st frame, card give it the frame and draws 1/3 of next one.
3) Monitor asks for 2nd frame, card just about finishes and gives 2nd frame
4) Monitor asks for 3rd frame, card only done 2/3 of it, so monitor shows the 2nd one again.
5) Monitor asks for 3rd frame, card gives it, next one coming up
6) Monitor asks for 4th frame, card just about finishes and gives it.

So in the first 6 frames of your game, you saw 3 frames of jerky, unsteady gameplay - the frames were not evenly spaced and it looked jerky.

Now you know what happens whe na card can't keep up with a monitor, but what about the other way around?

So, let's reverse it, the card now runs at 3 FPS and the monitor at 2 FPS.
1) Monitor asks for 1st frame, card gives it and does 1/2 the next one
2) Monitor asks for 2nd frame, card gives it the now completed 3rd frame.
3) Monitor asks for 3rd frame, too late! the card has already finished the 4th frame and 1/2 of the 5th, so monitor grabs the 4th and shows that instead.
4) Monitor asks for 4th frame, card has already finished the 5th frame and 1/2 of the 6th, so monitor shows that instead.

so you see, with the card running away in front with 3fps, in the first 4 frames of the game, you see 4 frames, but they are not sequential, and so the game appears jerky even though your card is breezing through it!

That's where Vsync comes in - it stop the card going any faster than the monitor, so that every time the monitor is ready for a frame, the card just about finishes it and hands it over one at a time, so that the image is smooth and avoids "tearing", which occurs sometimes when the card shoves an extra bit of a frame to the monitor each time, so that it appears a line is either quickly or slowly moving down the screen, making the whole scene look disjointed.

Have a look:




So, if your computer can handle it, (looks at andrew + luciel ) I'd suggest putting the refresh rate as high as your monitor allows, and turning Vsync on.

Phew... Hope that's readable enough - it's hard to type with a short sleeve in 15 degrees C

Gahhh!!! Math!!!
Let me see if I get this then...

If your computer is powerful enough to produce stable in game framrates in excess of 70 fps, then you want your monitor set at 70 hz or as high of a refresh rate as it can support?

If thats the case, then you want to also enable Vsync so that your card isn't churning out more frames than your monitor can handle and causing screen tearing.

So in my case and with my computer and monitor setup, I definately want to make my refresh rate as high as possible. I also probably want to enable Vsync for most games, with the exception of a game like Crysis (where its a struggle to get above 25 fps in some spots)

Gahhh!!! Math!!!
Let me see if I get this then...

If your computer is powerful enough to produce stable in game framrates in excess of 70 fps, then you want your monitor set at 70 hz or as high of a refresh rate as it can support?

If thats the case, then you want to also enable Vsync so that your card isn't churning out more frames than your monitor can handle and causing screen tearing.

So in my case and with my computer and monitor setup, I definately want to make my refresh rate as high as possible. I also probably want to enable Vsync for most games, with the exception of a game like Crysis (where its a struggle to get above 25 fps in some spots)

What the...

I played crysis all on max through the whole game without a single lag bit, and your system is better than mine and you had lag at a point? something´s not right there.

Oh and SDW, awesome explanation, i couldn´t have written it better myself!

I think you're right, Im not getting the performance I expected to be getting when I built my system. I think part of it has to do with my FSB not being timed correctly with my memory. I was told it has something to do with the speed and the multiplier and running it unlinked...
I need to read up on how to do that. If anybody is knowledgable in that feel free to educate me there as well.

Yeah, I played Crysis (64-bit) with everything at least on high, with textures, shaders, and a few other things on very high, 1280 x 1024 resolution, no AA, and was getting at between 25-30 fps in large open areas choppy sometimes when a lot starts happening on screen, but playable. As soon as the island got frozen, I watched my fps drop to 6. I had to drop everything to the lowest settings to get my framerate back between 25-30. Everything looks like ass now. It totally ruins the experience you had while you playing the first half of the game.

Andrew, you've hit the nail on the head there - on such an amazing system as yours, you want Vsync on unless there is some reason for not doing so, and you want your refresh rate as high as possible (don't set it higher than your monitor can display, although you should be safer with LCDs. My CRT blew up when I set it to 75 Hz.)

Oh yes I forgot - when you test you want vsync off, as well as any sorft of FPS limiter you may have, because then you get the max your card is capable of. you can turn it back on after testing of course

Well that's fine, but I guarantee you will not see a difference between 50-60+ fps. Also, if you read the part where the card is going faster than the monitor in my post, you can see that you are actually getting slightly more choppy gameplay, rather than at the "default" 75fps. You can probably turn VSync on and turn the graphical goodies up if you are getting about 120 fps!

I have Crysis, though I've not played that much, but I've got up to where you fight some tanks, and I've never noticed any serious lag - some blips when loading textures, due to my slow hard drive (though it's brand new) but nothign serious.

Could just be a display driver problem, if you haven't already found a cause.