GeForce GT 420 vs Radeon HD 7850

Intro

Compare all of that to the Radeon HD 7850, which has a clock speed of 860 MHz and a GDDR5 memory frequency of 1200 MHz. It also features a 256-bit bus, and uses a 28 nm design. It is comprised of 1024 SPUs, 64 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 7850		130 Watts
	Difference: 80 Watts (160%)

Memory Bandwidth

In theory, the Radeon HD 7850 should perform quite a bit faster than the GeForce GT 420 in general. (explain)

Radeon HD 7850		153600 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 124800 (433%)

Texel Rate

The Radeon HD 7850 should be a lot (more or less 883%) faster with regards to anisotropic filtering than the GeForce GT 420. (explain)

Radeon HD 7850		55040 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 49440 (883%)

Pixel Rate

The Radeon HD 7850 will be much (about 883%) faster with regards to FSAA than the GeForce GT 420, and also will be capable of handling higher screen resolutions better. (explain)

Radeon HD 7850		27520 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 24720 (883%)

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 (measured in megabytes per second) that can be moved past the external memory interface within a second. It is calculated by multiplying the interface width by its memory clock speed. If the card has DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's 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 number of texture units by the core speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly record 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 core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as 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 - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.