Graphics Card's Memory: Does the size only matter or Are there other things to consider also?

I've seen a lot of bragging "My PC has got a 1GB graphics card". But is the VRAM size only the yardstick of a graphics card's performance?? Most people think so. "If my card has more memory, it will perform more". This is the common notion. This is true to a certain extent. More VRAM means more memory space to hold textures & more resolutions and detailed textures are possible.

There are three major factors that people usually skip or ignore while choosing a graphics card. Those are:

1) The Graphics Processor (GPU): This is the brain of the graphics card. All graphics processing is done on this chip. When we say "Geforce 9600GT", we are actually referring tho the graphics processor. The faster the GPU, the faster would be the performance. This is the first point: There is no point having a graphics card with 1GB memory & a slow GPU. Its like having a PII with 1GB RAM. The ram will be able to hold a lot of data, but with a slow processor there is no use having such amounts RAM as the processor is not fast enough to process all those data in an efficient manner. Unprocessed data is of no use, to process all those information fed by the ram, a really fast processor is required. Saying which GPU is fast, faster & fastest is not easy. Do your bit of homework before selecting one..

2) VRAM Type: Currently there are three types of VRAM being used in graphics card. DDR2, GDDR3 & GDDR5 (in the ascending order of performance).  The difference being the speeds at which they operate. Why the VRAM needs to be speedy when the primary purpose of it is to hold data??. If the VRAM is faster it can pump in data much faster into the GPU & the GPU will be able to write data more quickly. This will increase the efficiency of the GPU & will help it do more operations per unit time. Also this makes sure that the GPU is not starved of data & is not running at its full potential.

3) Bus Width: Bus width means the number of bus lines that connect the GPU & VRAM. Its number determine the amount of data the gpu will be able to access simultaneously. A 64-bit wide bus means the gpu can access 64-bits of data in one ram access cycle. Bus Width along with the VRAM speed determine the memory bandwith (the amount of data that the GPU can access from the VRAM, usually expressed in GB/s). This is one important performance criteria.

So beware when you argue the next time with someone that your 9400GS 1GB DDR2 is really faster than his 9800GT 512MB DRR3 since it has twice the VRAM..