Vertical Sync and Antialiasing explained


SMART GAMING: Graphical tweaks to enhance your 3D gaming experience

THERE comes a time in every gamers life when he or she is forced to lower some graphical settings in order the play the hardware-intense game they have so longed for. Well I’ll be damned if I ever have to sacrifice my 1920×1080 resolution, texture quality and surround sound in order to play any game smoothly. If absolutely necessary, I find myself turning off vertical sync and lowering antialiasing – not really knowing what these do. So, if you’ve been pondering what these are yourself, here’s what each do in a nutshell.

Before we begin it is important to understand that all digitalised movement, whether it be in a computer game or a film, is created by several, rapidly displayed still frames (moving pictures) which we perceive as movement. Such perception differs from person to person, but generally 25 FPS (frames per second) is sufficient for the human eye to perceive smooth and fluid motion.

Antialiasing
antialiasing before and afterAs many of us know, all computer images are made up of thousands of colorful building blocks called pixels. These can created a step-effect along curved or diagonal lines – an effect known as aliasing.

What antialiasing therefore does is smooth out these jagged lines/edges by changing the surrounding pixels to varying shades of gray or colour in order to blend the sharp edges into the background.

More technically, antialiasing “… tells your graphics hardware how many pixel samples to take around the area to antialias – the higher the number, the more pixel samples are used to blend jagged lines, and hence the smoother the image will appear at the cost of greater processing power and hence lower performance.”
www.tweakguides.com

Because higher resolutions make use of more pixels to draw an image (which results in smoother curved lines and edges) antialiasing is most effective when playing a game using a lower resolution than intended.

It is important to note that antialiasing is a graphically intensive task which uses large amounts of video memory and can therefore dramatically reduce performance. This is why most games and graphics cards today offer different levels of antialiasing for you to enable (e.g. 2x, 4x, 8x and even 16x). Of course disabling antialiasing altogether will result in maximum performance.

Antialiasing types
There are different methods of antialiasing that fall under different guises depending on the 3D application being run. Antialiasing settings may be found under any of the following:

  • Multisampling
  • Supersampling
  • Coverage Sampling Antialiasing
  • Temporal and Adaptive Antialiasing (used by ATI graphics cards)
  • Quincunx, Transparency, and Gamma Correct Antialiasing (used by Nvidia graphics cards)

Each antialiasing setting may offer different tweaks but they generally all have the same effect. Experiment to see which effects you most prefer.

Solution
Antialiasing is useful for reducing the effect of jagged lines and edges, which are more prevalent at lower resolutions. The higher it is set, the smoother edges will be, but remember that this is a graphically intense process that may result is poorer performance. Also, if your resolution is set at the max, antialiasing can be disabled altogether without any loss in quality.

Vertical Sync
Gaming graphics cardVertical Synchronisation (also called Vertical Sync, or simply VSync for short) synchronises the actions of your graphics card with your monitor. In other words, VSync matches your monitor’s refresh rate or frequency with a 3D application’s frame rate or FPS. In other, other words, Vsync doesn’t allow your frame rate to exceed your monitor’s refresh rate and ensures that only whole frames are seen on-screen at any given time. The refresh rate (e.g. 60Hz) is how many times your screen can refresh itself in a single second.

When VSync is enabled
When VSync is enabled, your graphics card is forced to wait for your monitor to signal when it’s ready for a new frame before supplying a single whole frame, each and every time. Your FPS will become capped at a maximum equal to your monitor’s refresh rate. So if your refresh rate is the standard 60Hz for example, your frame rate can only reach a maximum of 60 FPS.

However, so long as your graphics card can always render a frame faster than your screen can refresh itself, enabling VSync will not reduce your average frame rate. All that will happen is that your FPS will be capped to a maximum equivalent to the refresh rate, which is not necessarily a bad thing at all. 60 FPS should be more than enough to play any game smoothly.

Graphical glitches only arise when your graphics card works significantly faster than your monitor. If your graphics card produces frames faster than what your screen can actually display at any one time, overlapping frames may occur. Having VSync enabled would eliminate this little nuisance.

When VSync is disabled
When vertical sync is disabled, your graphics card and monitor may, quite literally, go out of sync, and result in a graphical phenomenon called “tearing”. This results in onscreen images appearing to be slightly out of alignment or ‘torn’ in parts whenever there is any significant movement.

According to http://www.tweakguides.com “Tearing does absolutely no damage to your graphics card or monitor. It just highlights the physical limitation of your monitor in keeping up with the graphics card when the two aren’t synchronized.”

In a nutshell, having VSync disabled in any game is the most trouble-free method of gaining the fastest possible performance as it allows your graphics card to operate unhindered. This also appears to be the best solution for games in which your frame rate is not very high.

Graphical synchronisation is really only a problem if your graphics card is new and potent whilst your screen is looking a little out-dated. It is not generally an issue for newer LCD screens (where a refresh rate of 60Hz is perfectly acceptable) but rather a remnant of older CRT monitor technology.

Solution
So, it seems that there are pros and cons regarding Vertical Sync. With it switched off, tearing can occur whenever your graphics card and monitor go out of sync (usually in fast-paced games), which can be really annoying. However, with VSync switched on, your FPS can often fall by up to 50% which is no laughing matter. This can be resolved on many systems by enabling Triple Buffering, however, this may affect your game’s performance further.

Many would recommend setting your VSync to ‘Application Preference’ in your graphics control panel and simply let your PC decide what’s best. It’s clear that there’s no obvious choice when it comes to VSync, but so long as you understand what it does, you can make an educated choice on a case by case basis.

Further reading
For a more in-depth explanation of how the internal bits of your PC operate and how to make the most out of graphical tweaks, this is a fantastical and simply written resource that explains it all: www.tweakguides.com

Related Post: A Dummies Guide to Overclocking

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