GeForce GT 640 DDR3 vs Radeon HD 4730

Intro

Compare those specifications to the Radeon HD 4730, which features GPU core speed of 700 MHz, and 512 MB of GDDR5 RAM set to run at 900 MHz through a 128-bit bus. It also is comprised of 640(128x5) Stream Processors, 32 Texture Address Units, and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 4730		140 Watts
	Difference: 75 Watts (115%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4730 should be 1% faster than the GeForce GT 640 DDR3 in general, due to its greater bandwidth. (explain)

Radeon HD 4730		57600 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 576 (1%)

Texel Rate

The GeForce GT 640 DDR3 will be quite a bit (approximately 29%) more effective at AF than the Radeon HD 4730. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 4730		22400 Mtexels/sec
	Difference: 6400 (29%)

Pixel Rate

The GeForce GT 640 DDR3 is quite a bit (more or less 157%) more effective at FSAA than the Radeon HD 4730, and also should be capable of handling higher screen resolutions without slowing down too much. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 4730		5600 Mpixels/sec
	Difference: 8800 (157%)

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 largest amount of data (measured in megabytes per second) that can be transferred over the external memory interface in a second. It is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.