GeForce 9500 GT 1GB GDDR3 vs GeForce GT 640 DDR3

Intro

Compare those specs to the GeForce GT 640 DDR3, which comes with a clock frequency of 900 MHz and a DDR3 memory speed of 1782 MHz. It also makes use of a 128-bit memory bus, and makes use of a 28 nm design. It is made up of 384 SPUs, 32 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9500 GT 1GB GDDR3		50 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 15 Watts (30%)

Memory Bandwidth

Theoretically speaking, the GeForce GT 640 DDR3 should be 123% faster than the GeForce 9500 GT 1GB GDDR3 in general, because of its greater bandwidth. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce 9500 GT 1GB GDDR3		25600 MB/sec
	Difference: 31424 (123%)

Texel Rate

The GeForce GT 640 DDR3 is a lot (more or less 227%) more effective at anisotropic filtering than the GeForce 9500 GT 1GB GDDR3. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce 9500 GT 1GB GDDR3		8800 Mtexels/sec
	Difference: 20000 (227%)

Pixel Rate

If running with a high resolution is important to you, then the GeForce GT 640 DDR3 is the winner, by far. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce 9500 GT 1GB GDDR3		4400 Mpixels/sec
	Difference: 10000 (227%)

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 information (in units of megabytes per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory clock speed. If the card has DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total number of texture units of the card 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 processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.