GeForce GT 640 DDR3 vs Radeon HD 4670 512MB

Intro

Compare all of that to the Radeon HD 4670 512MB, which has a core clock frequency of 750 MHz and a GDDR4/GDDR3/DDR3/DDR2 memory frequency of 1000 MHz. It also makes use of a 128-bit memory bus, and makes use of a 55 nm design. It features 320(64x5) SPUs, 32 TAUs, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 4670 512MB		70 Watts
	Difference: 5 Watts (8%)

Memory Bandwidth

Performance-wise, the GeForce GT 640 DDR3 should in theory be quite a bit superior to the Radeon HD 4670 512MB in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
Radeon HD 4670 512MB		32000 MB/sec
	Difference: 25024 (78%)

Texel Rate

The GeForce GT 640 DDR3 will be a small bit (more or less 20%) better at AF than the Radeon HD 4670 512MB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 4670 512MB		24000 Mtexels/sec
	Difference: 4800 (20%)

Pixel Rate

If using high levels of AA is important to you, then the GeForce GT 640 DDR3 is a better choice, by far. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 4670 512MB		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 maximum amount of data (counted in MB per second) that can be moved across the external memory interface within a second. It's worked out by multiplying the card's interface width by its memory speed. If the card has DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

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