GeForce GT 420 vs Radeon HD 7970

Intro

Compare all of that to the Radeon HD 7970, which features a core clock frequency of 925 MHz and a GDDR5 memory frequency of 1375 MHz. It also makes use of a 384-bit bus, and uses a 28 nm design. It is made up of 2048 SPUs, 128 TAUs, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 7970		250 Watts
	Difference: 200 Watts (400%)

Memory Bandwidth

Theoretically, the Radeon HD 7970 should be much faster than the GeForce GT 420 in general. (explain)

Radeon HD 7970		264000 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 235200 (817%)

Texel Rate

The Radeon HD 7970 is much (approximately 2014%) more effective at anisotropic filtering than the GeForce GT 420. (explain)

Radeon HD 7970		118400 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 112800 (2014%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 7970 is a better choice, by far. (explain)

Radeon HD 7970		29600 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 26800 (957%)

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 information (counted in MB per second) that can be moved past the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.