GeForce GT 420 vs Radeon HD 7950

Intro

Compare those specs to the Radeon HD 7950, which uses a 28 nm design. AMD has set the core speed at 800 MHz. The GDDR5 memory is set to run at a frequency of 1250 MHz on this particular model. It features 1792 SPUs along with 112 TAUs 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 7950		200 Watts
	Difference: 150 Watts (300%)

Memory Bandwidth

Theoretically, the Radeon HD 7950 should perform quite a bit faster than the GeForce GT 420 in general. (explain)

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

Texel Rate

The Radeon HD 7950 should be a lot (more or less 1500%) better at AF 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 (more or less 814%) faster with regards to full screen anti-aliasing than the GeForce GT 420, and should be capable of handling higher screen 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: Memory bandwidth is the max amount of data (in units of megabytes per second) that can be moved over the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory speed. In the case of DDR memory, 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 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 figure is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at handling 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 the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on many 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.