GeForce GT 420 vs Radeon HD 4770

Intro

Compare that to the Radeon HD 4770, which comes with clock speeds of 750 MHz on the GPU, and 800 MHz on the 512 MB of GDDR5 RAM. It features 640(128x5) SPUs as well as 32 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 4770		80 Watts
	Difference: 30 Watts (60%)

Memory Bandwidth

In theory, the Radeon HD 4770 is 78% quicker than the GeForce GT 420 in general, because of its higher bandwidth. (explain)

Radeon HD 4770		51200 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 22400 (78%)

Texel Rate

The Radeon HD 4770 is a lot (about 329%) more effective at anisotropic filtering than the GeForce GT 420. (explain)

Radeon HD 4770		24000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 18400 (329%)

Pixel Rate

The Radeon HD 4770 is quite a bit (about 329%) more effective at anti-aliasing than the GeForce GT 420, and also will be capable of handling higher screen resolutions better. (explain)

Radeon HD 4770		12000 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 9200 (329%)

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 (measured in MB per second) that can be transported past the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total texture units of the card by the core clock 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 a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.