GeForce GT 420 vs Radeon HD 7950

Intro

Compare that to the Radeon HD 7950, which comes with clock speeds of 800 MHz on the GPU, and 1250 MHz on the 1536 MB of GDDR5 RAM. It features 1792 SPUs as well as 112 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

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

Memory Bandwidth

In theory, the Radeon HD 7950 will be 733% faster than the GeForce GT 420 in general, because of its greater bandwidth. (explain)

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

Texel Rate

The Radeon HD 7950 will be a lot (about 1500%) more effective at anisotropic filtering than the GeForce GT 420. (explain)

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

Pixel Rate

The Radeon HD 7950 will be a lot (about 814%) more effective at AA than the GeForce GT 420, and should be able to handle higher resolutions better. (explain)

Radeon HD 7950		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 maximum amount of data (counted in MB per second) that can be transported over the external memory interface within a second. It's worked out by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This is calculated 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 applied in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the core 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 rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.