GeForce GT 320 vs GeForce GT 640 DDR3

Intro

Compare those specifications to the GeForce GT 640 DDR3, which has a GPU core clock speed of 900 MHz, and 2048 MB of DDR3 memory running at 1782 MHz through a 128-bit bus. It also is made up of 384 Stream Processors, 32 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 320		43 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 22 Watts (51%)

Memory Bandwidth

The GeForce GT 640 DDR3 should theoretically perform much faster than the GeForce GT 320 in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce GT 320		25280 MB/sec
	Difference: 31744 (126%)

Texel Rate

The GeForce GT 640 DDR3 should be quite a bit (about 122%) faster with regards to texture filtering than the GeForce GT 320. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce GT 320		12960 Mtexels/sec
	Difference: 15840 (122%)

Pixel Rate

If using a high resolution is important to you, then the GeForce GT 640 DDR3 is superior to the GeForce GT 320, by far. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce GT 320		4320 Mpixels/sec
	Difference: 10080 (233%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the maximum amount of data (in units of megabytes per second) that can be transferred past the external memory interface in one second. The number is worked out by multiplying the interface width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.