GeForce 8800 GS vs GeForce GT 640 DDR3

Intro

Compare all that to the GeForce GT 640 DDR3, which makes use of a 28 nm design. nVidia has clocked the core frequency at 900 MHz. The DDR3 RAM works at a frequency of 1782 MHz on this particular card. It features 384 SPUs as well as 32 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce 8800 GS		105 Watts
	Difference: 40 Watts (62%)

Memory Bandwidth

Theoretically speaking, the GeForce GT 640 DDR3 should be quite a bit faster than the GeForce 8800 GS overall. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce 8800 GS		38400 MB/sec
	Difference: 18624 (49%)

Texel Rate

The GeForce GT 640 DDR3 should be a small bit (about 9%) faster with regards to AF than the GeForce 8800 GS. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce 8800 GS		26400 Mtexels/sec
	Difference: 2400 (9%)

Pixel Rate

The GeForce GT 640 DDR3 should be much (more or less 118%) more effective at anti-aliasing than the GeForce 8800 GS, and will be able to handle higher screen resolutions more effectively. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce 8800 GS		6600 Mpixels/sec
	Difference: 7800 (118%)

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 max amount of data (in units of megabytes per second) that can be moved past the external memory interface within a second. It's worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one 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 better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines 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 fill rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.