GeForce GT 640 DDR3 vs GeForce GTX 285 1GB

Intro

Compare those specs to the GeForce GTX 285 1GB, which makes use of a 55 nm design. nVidia has clocked the core speed at 648 MHz. The GDDR3 memory runs at a speed of 1242 MHz on this particular model. It features 240 SPUs as well as 80 Texture Address Units and 32 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTX 285 1GB		204 Watts
	Difference: 139 Watts (214%)

Memory Bandwidth

The GeForce GTX 285 1GB should in theory be quite a bit faster than the GeForce GT 640 DDR3 overall. (explain)

GeForce GTX 285 1GB		158976 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 101952 (179%)

Texel Rate

The GeForce GTX 285 1GB should be quite a bit (about 80%) more effective at AF than the GeForce GT 640 DDR3. (explain)

GeForce GTX 285 1GB		51840 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 23040 (80%)

Pixel Rate

If using high levels of AA is important to you, then the GeForce GTX 285 1GB is a better choice, by far. (explain)

GeForce GTX 285 1GB		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: Bandwidth is the maximum amount of information (counted in megabytes per second) that can be transported over the external memory interface in one second. It is calculated by multiplying the card's interface width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.