GeForce GT 420 vs Radeon HD 7770

Intro

Compare those specs to the Radeon HD 7770, which features a core clock frequency of 1000 MHz and a GDDR5 memory speed of 1125 MHz. It also uses a 128-bit bus, and makes use of a 28 nm design. It is made up of 640 SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 7770		80 Watts
	Difference: 30 Watts (60%)

Memory Bandwidth

Performance-wise, the Radeon HD 7770 should theoretically be quite a bit superior to the GeForce GT 420 in general. (explain)

Radeon HD 7770		72000 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 43200 (150%)

Texel Rate

The Radeon HD 7770 is much (about 614%) faster with regards to texture filtering than the GeForce GT 420. (explain)

Radeon HD 7770		40000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 34400 (614%)

Pixel Rate

The Radeon HD 7770 is a lot (about 471%) faster with regards to anti-aliasing than the GeForce GT 420, and will be capable of handling higher resolutions better. (explain)

Radeon HD 7770		16000 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 13200 (471%)

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 megabytes per second) that can be transported across the external memory interface within a second. It is worked out by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This is calculated by multiplying the total number of texture units by the core speed of the chip. The higher 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 the video card can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.