GeForce GT 420 vs Radeon HD 7950 3GB

Intro

Compare all of that to the Radeon HD 7950 3GB, which comes with a GPU core clock speed of 800 MHz, and 3072 MB of GDDR5 memory set to run at 1250 MHz through a 384-bit bus. It also is made up of 1792 Stream Processors, 112 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 150 Watts (300%)

Memory Bandwidth

Performance-wise, the Radeon HD 7950 3GB should theoretically be a lot superior to the GeForce GT 420 in general. (explain)

Radeon HD 7950 3GB		240000 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 211200 (733%)

Texel Rate

The Radeon HD 7950 3GB will be much (about 1500%) more effective at texture filtering than the GeForce GT 420. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 84000 (1500%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 7950 3GB is a better choice, by far. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 22800 (814%)

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 (counted in megabytes per second) that can be transported over the external memory interface in a second. It's calculated by multiplying the card's bus width by its memory speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.