GeForce GT 640 DDR3 vs Radeon HD 4670 1GB

Intro

Compare those specifications to the Radeon HD 4670 1GB, which features a core clock speed of 750 MHz and a GDDR4/GDDR3/DDR3/DDR2 memory speed of 1100 MHz. It also features a 128-bit bus, and makes use of a 55 nm design. It is made up of 320(64x5) SPUs, 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 4670 1GB		70 Watts
	Difference: 5 Watts (8%)

Memory Bandwidth

As far as performance goes, the GeForce GT 640 DDR3 should theoretically be quite a bit superior to the Radeon HD 4670 1GB in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
Radeon HD 4670 1GB		35200 MB/sec
	Difference: 21824 (62%)

Texel Rate

The GeForce GT 640 DDR3 is just a bit (approximately 20%) more effective at anisotropic filtering than the Radeon HD 4670 1GB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 4670 1GB		24000 Mtexels/sec
	Difference: 4800 (20%)

Pixel Rate

The GeForce GT 640 DDR3 should be a lot (more or less 140%) more effective at FSAA than the Radeon HD 4670 1GB, and also should be able to handle higher resolutions while still performing well. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 4670 1GB		6000 Mpixels/sec
	Difference: 8400 (140%)

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 (in units of megabytes per second) that can be transferred past the external memory interface within a second. The number is worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics 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 maximum number of pixels that the graphics chip could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.