It would only allow a performance increase if the data from the memory was not reaching the gpu at a fast enough rate. If the gpu is being fed enough data then you would not see an increase.
The amount of data that can be transferred over a bus is a relationship between the frequency that the information is sent at and the amount of bits(always multiple's of eight) that can be sent at once. If you have fast enough memory then you can afford a narrower bus width, if you have slow ram then you would like a wider one and if you can have both fast ram and a wide bus width then it is probably overkill.
The Sapphire card will outperform the PowerColor card simply due to the fact that it has twice the memory bandwidth, allowing the GPU to access the memory much faster. The difference in performance may not be much in some titles, but it could be rather significant in others.
So, if you're comparing two cards with the exact same core GPU in them that have different bus-widths, then the faster of the two would be the better performer. However, when comparing different GPUs, say for example the HD4850 (256-bit) and HD5770 (128-bit), the higher bus-width of the 4850 does not make it a faster card than the 5770, as the 5770's GPU is actually faster than the 4850's core.
Basically, you have to be comparing apples with apples in the first place. Get it?
Yeah, I figured that's exactly why you wanted clarification. I just wanted to get the point across that a card with a faster memory interface doesn't guarantee a higher performing card unless you're also dealing with an identical GPU to begin with. In cases where the GPU is the same on both cards and the memory bus speeds are different, then the card with the higher bus speed will typically outperform the other.
ok i understand now .... other people telling me about the bit means video card graphics color more bit good game graphics quality ... some saying windows xp if you have a 128bit VC u can set up the color quality from 32bit up to 128bit depends on what VC bit use. but the VC has a chance to destroy if you run the 128 bit on the color quality ^_^ .... base on your post i think they all wrong ^_^
Ahh, I see. Colour bit depth is something different. That defines how many individual shades of colours you can display. Usually you have red, green and blue as the primary colours represnted by 8 bits of data giving 256 levels of the colour from 0-255.
Also note that not all monitors support 8 bits with many only supporting 6 bits but using blending techniques to fake the other colours.
In 32 bit colour I do not actually know what the final 8 bits do as they are not colour related.