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Old March 10, 2011, 02:10 PM
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Originally Posted by Shadowmeph View Post
I am still wondering why most if not all the newer video cards are 256bit. I thought that the higher the bit the better the card I have also thought that a card like the 6990 4Gb would be at least 512bit but should be half of the memory so in this case 2Gbits.

Well, technically the 6990 is 2x256 bit bus.... but I think you are referring to past cards with a very wide bus:

Typically, back in the day, the only way to increase memory bandwidth was to increase the width of the bus (back in the ddr2, ddr3, gddr3 ram days). But nowadays, there is no need for a 512bit bus, since the advent of gddr5 memory modules (and, regrettably, gddr4 memory) which post faster speeds than gddr3 memory... thus increasing the memory bandwidth without increasing the size of the bus.

One of the reasons why the gtx 280 was so hot and loud and expensive is because it has a 512bit bus, which is extremely expensive to produce (in comparison to 256bit or 384bit), and it takes up a lot of space on the GPU die itself... leading to less GPU's manufactured PER wafer of silicon... add to that the yield rate on the silicon and you've got one large and expensive GPU.

Hope that clears things up for you..

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