GeForce 9500 GT 512MB GDDR3 vs GeForce GT 640 DDR3

Intro

Compare those specs to the GeForce GT 640 DDR3, which has a core clock speed of 900 MHz and a DDR3 memory frequency of 1782 MHz. It also makes use of a 128-bit bus, and uses a 28 nm design. It features 384 SPUs, 32 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9500 GT 512MB GDDR3		50 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 15 Watts (30%)

Memory Bandwidth

The GeForce GT 640 DDR3, in theory, should perform much faster than the GeForce 9500 GT 512MB GDDR3 in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce 9500 GT 512MB GDDR3		25600 MB/sec
	Difference: 31424 (123%)

Texel Rate

The GeForce GT 640 DDR3 will be much (more or less 227%) more effective at texture filtering than the GeForce 9500 GT 512MB GDDR3. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce 9500 GT 512MB GDDR3		8800 Mtexels/sec
	Difference: 20000 (227%)

Pixel Rate

The GeForce GT 640 DDR3 is a lot (about 227%) more effective at FSAA than the GeForce 9500 GT 512MB GDDR3, and also should be capable of handling higher resolutions without losing too much performance. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce 9500 GT 512MB 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: Bandwidth is the max amount of data (in units of MB per second) that can be transferred past the external memory interface in a second. It is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel 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 potential to reach the max fill rate.