You might notice the grid lines and stone edges can get blocky, which is called aliasing. The effect which prevents this is called antialiasing. glGo supports two antialias modes, a third is accessible via the configuration of your 3D driver.
Two simple but quite effective antialias settings affect the drawing of lines and stones only. This are the line and stone antialias settings in glGo. You find them in themenu.
Blending must be enabled, else antialiasing will show no effect.
This will affect the grid on the goban and smooth the lines when rotating the board. If turned off, the lines will appear blocky. The quality of this effect depends on the capability of your graphic card.
This will affect the board of stones to appear smooth. The effect should be obvious when toggling this on and off. This is a recommended feature which does not affect performance much and even is fast in software mode, so there is little reason to turn this off.
Scene antialiasing will improve not only the lines and stones but the complete display. To enable this feature, turn on themenu item in glGo. You can configure if low or high quality should be used. This scene antialiasing effect can be very slow on older hardware. It only runs in hardware mode on very new cards (hardware supported accumulation buffer, to be specific), so this is quite slow when it is not supported by the card, as the CPU has to do the work. If you have a fast computer, on low quality setting it might still be performant enough. But with lots of stones on the board and on high quality settings this eats CPU power for breakfast unless your card has the above mentioned hardware accumulation buffer. I think Geforce4 has it, but not sure.
Modern graphic cards have a feature called Multisampling, which will also smooth the overall scene. glGo will automatically turn multisampling on if it is supported by the hardware.
You need to enable full screen antialiasing (FSAA) in your 3D driver. You can access this in the 3D driver configuration dialog, for NVidia cards (sorry, no idea about the ATI and Matrox drivers) there is a slider which allows the FSAA detail setting. On Linux you can control this feature by setting an environment variable, see the documentation of your driver. Unfortunately this configuration is not accessible from the application itself. FSAA is supported by most recent graphic cards.
You might need to play a little with the settings and your 3D driver configuration to find good settings which meet your needs for quality and performance.
On a medium to low-end computer you should be Ok if you have a recent 3D driver installed (see section requirements) and enable Blending, Line and Stone antialias, Textures and Light. Keep the Scene antialias in glGo disabled. If your card supports it, enable FSAA in the driver configuration. On a high-end computer give the glGo Scene antialiasing a try and see how much it drops the performance.