1GB DDR3 128bit vs 1GB DDR5 64bit??

beavermml

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Oct 16, 2010
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my fren ask me to choose a graphic card between GT630 4GB DDR3 128bit and GT640 1GB DDR5 64bit.. both belong to the same price

and i told him that GT640 ( which is obvious by the model number alone ) is better but he is skeptical with 64bit memory part..

care to explain?
 
Solution
yes, the GT640 is better, it has ddr5 with 64-bit memory interface width, but the memory is clocked at 5000Mhz vs 1800Mhz from DDR3/128bit. in translation: a bandwidth of 40GB/s > 28.5GB/s. ddr5 version is faster (this is a part that matter in games). I heard that GT640 with ddr5/64bit, perform the same as a GTS450. that 4gb ddr3 is useless. you really can't play very high resolution/textures that will require 4gb, and if he can fill 4gb of textures, it will be slow. GT640 card is good for 720p gaming.

http://www.geforce.com/hardware/desktop-gpus/geforce-gt-630/specifications

http://www.geforce.com/hardware/desktop-gpus/geforce-gt640/specifications

look at the bandwidth, cuda cores, and texture fillrate. and the kepler version which...

razvan_mz

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Jun 25, 2011
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yes, the GT640 is better, it has ddr5 with 64-bit memory interface width, but the memory is clocked at 5000Mhz vs 1800Mhz from DDR3/128bit. in translation: a bandwidth of 40GB/s > 28.5GB/s. ddr5 version is faster (this is a part that matter in games). I heard that GT640 with ddr5/64bit, perform the same as a GTS450. that 4gb ddr3 is useless. you really can't play very high resolution/textures that will require 4gb, and if he can fill 4gb of textures, it will be slow. GT640 card is good for 720p gaming.

http://www.geforce.com/hardware/desktop-gpus/geforce-gt-630/specifications

http://www.geforce.com/hardware/desktop-gpus/geforce-gt640/specifications

look at the bandwidth, cuda cores, and texture fillrate. and the kepler version which is newer.
 
Solution
First of all, either card is not considered as more than an entry level gaming card.

The GT640 will perform the better of the two, but not by that much.

The amount of vram on a card is often more marketing than anything else.
Read this, for example: http://www.pugetsystems.com/labs/articles/Video-Card-Performance-2GB-vs-4GB-Memory-154/
 


My point was that vram is not a performance issue.
Individual specs like vram, Gddr speeds, # of shaders, etc... all go into the performance numbers and probably should not be used individually as selection criteria.
Benchmarks are more appropriate for selection. Even that is changing a bit, since simple FPS numbers do not tell the whole story.
Consistency of frame presentation is a new metric.