GeForce GT 420 vs Radeon HD 5870

Intro

Compare those specifications to the Radeon HD 5870, which comes with core speeds of 850 MHz on the GPU, and 1200 MHz on the 1024 MB of GDDR5 memory. It features 1600(320x5) SPUs along with 80 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 5870		188 Watts
	Difference: 138 Watts (276%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 5870 should be 433% faster than the GeForce GT 420 overall, due to its higher bandwidth. (explain)

Radeon HD 5870		153600 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 124800 (433%)

Texel Rate

The Radeon HD 5870 should be much (about 1114%) faster with regards to texture filtering than the GeForce GT 420. (explain)

Radeon HD 5870		68000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 62400 (1114%)

Pixel Rate

The Radeon HD 5870 should be quite a bit (more or less 871%) more effective at full screen anti-aliasing than the GeForce GT 420, and will be able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 5870		27200 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 24400 (871%)

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: Memory bandwidth is the max amount of information (counted in megabytes per second) that can be moved over the external memory interface in one second. It's worked out by multiplying the card's bus width by its memory clock speed. In the case of DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel 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.