GeForce GT 640 DDR3 vs GeForce GTX 285 2GB

Intro

Compare those specs to the GeForce GTX 285 2GB, which has GPU clock speed of 648 MHz, and 2048 MB of GDDR3 RAM set to run at 1242 MHz through a 512-bit bus. It also features 240 SPUs, 80 TAUs, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTX 285 2GB		204 Watts
	Difference: 139 Watts (214%)

Memory Bandwidth

The GeForce GTX 285 2GB should theoretically perform much faster than the GeForce GT 640 DDR3 overall. (explain)

GeForce GTX 285 2GB		158976 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 101952 (179%)

Texel Rate

The GeForce GTX 285 2GB should be a lot (more or less 80%) better at AF than the GeForce GT 640 DDR3. (explain)

GeForce GTX 285 2GB		51840 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 23040 (80%)

Pixel Rate

The GeForce GTX 285 2GB will be much (about 44%) better at full screen anti-aliasing than the GeForce GT 640 DDR3, and also able to handle higher screen resolutions without slowing down too much. (explain)

GeForce GTX 285 2GB		20736 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 6336 (44%)

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 (counted in megabytes per second) that can be moved across the external memory interface in a second. It's worked out by multiplying the interface width by its memory speed. If the card has DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.