GeForce GT 420 vs Radeon HD 3870 1GB

Intro

Compare those specs to the Radeon HD 3870 1GB, which features core clock speeds of 775 MHz on the GPU, and 1125 MHz on the 1024 MB of GDDR4 memory. It features 320(64x5) SPUs as well as 16 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 3870 1GB		106 Watts
	Difference: 56 Watts (112%)

Memory Bandwidth

In theory, the Radeon HD 3870 1GB should be quite a bit faster than the GeForce GT 420 in general. (explain)

Radeon HD 3870 1GB		72000 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 43200 (150%)

Texel Rate

The Radeon HD 3870 1GB is quite a bit (more or less 121%) faster with regards to anisotropic filtering than the GeForce GT 420. (explain)

Radeon HD 3870 1GB		12400 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 6800 (121%)

Pixel Rate

The Radeon HD 3870 1GB should be much (approximately 343%) faster with regards to full screen anti-aliasing than the GeForce GT 420, and should be able to handle higher resolutions without slowing down too much. (explain)

Radeon HD 3870 1GB		12400 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 9600 (343%)

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 maximum amount of information (counted in MB per second) that can be transported past the external memory interface in a second. It's calculated by multiplying the interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This is worked out by multiplying the total number of texture units of the card by the core 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 applied per second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.