GeForce GT 240 GDDR5 1GB vs GeForce GT 640 DDR3

Intro

Compare all that to the GeForce GT 640 DDR3, which uses a 28 nm design. nVidia has clocked the core frequency at 900 MHz. The DDR3 memory works at a speed of 1782 MHz on this card. It features 384 SPUs along with 32 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GT 240 GDDR5 1GB		70 Watts
	Difference: 5 Watts (8%)

Memory Bandwidth

As far as performance goes, the GeForce GT 640 DDR3 should theoretically be a little bit better than the GeForce GT 240 GDDR5 1GB in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce GT 240 GDDR5 1GB		54400 MB/sec
	Difference: 2624 (5%)

Texel Rate

The GeForce GT 640 DDR3 should be much (approximately 64%) more effective at AF than the GeForce GT 240 GDDR5 1GB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce GT 240 GDDR5 1GB		17600 Mtexels/sec
	Difference: 11200 (64%)

Pixel Rate

The GeForce GT 640 DDR3 will be much (more or less 227%) faster with regards to full screen anti-aliasing than the GeForce GT 240 GDDR5 1GB, and will be able to handle higher screen resolutions while still performing well. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce GT 240 GDDR5 1GB		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 information (measured in megabytes per second) that can be moved across the external memory interface within a second. The number is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total amount of texture units by the core clock 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 in one second.

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