GeForce GT 420 vs Radeon HD 6770

Intro

Compare those specifications to the Radeon HD 6770, which comes with a clock frequency of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also features a 128-bit bus, and uses a 40 nm design. It is made up of 800 SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 6770		108 Watts
	Difference: 58 Watts (116%)

Memory Bandwidth

In theory, the Radeon HD 6770 will be 133% faster than the GeForce GT 420 overall, because of its greater data rate. (explain)

Radeon HD 6770		67200 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 38400 (133%)

Texel Rate

The Radeon HD 6770 will be quite a bit (approximately 543%) more effective at anisotropic filtering than the GeForce GT 420. (explain)

Radeon HD 6770		36000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 30400 (543%)

Pixel Rate

The Radeon HD 6770 is much (more or less 414%) better at AA than the GeForce GT 420, and capable of handling higher resolutions better. (explain)

Radeon HD 6770		14400 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 11600 (414%)

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 (counted in megabytes per second) that can be transported across the external memory interface within a second. It is calculated by multiplying the card's interface width by its memory speed. If it uses DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better 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 amount of texture map elements (texels) that are processed in one second. This is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better the texel rate, the better the video 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 number of pixels that the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.