GeForce GT 420 vs Radeon HD 6790

Intro

Compare all of that to the Radeon HD 6790, which makes use of a 40 nm design. AMD has set the core frequency at 840 MHz. The GDDR5 memory is set to run at a frequency of 1050 MHz on this particular card. It features 800 SPUs along with 40 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 6790		150 Watts
	Difference: 100 Watts (200%)

Memory Bandwidth

Theoretically, the Radeon HD 6790 should be a lot faster than the GeForce GT 420 in general. (explain)

Radeon HD 6790		134400 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 105600 (367%)

Texel Rate

The Radeon HD 6790 will be quite a bit (about 500%) better at AF than the GeForce GT 420. (explain)

Radeon HD 6790		33600 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 28000 (500%)

Pixel Rate

The Radeon HD 6790 should be quite a bit (approximately 380%) more effective at anti-aliasing than the GeForce GT 420, and also able to handle higher resolutions better. (explain)

Radeon HD 6790		13440 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 10640 (380%)

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 megabytes per second) that can be transferred past the external memory interface in one second. It's calculated by multiplying the card's bus width by its memory speed. In the case of DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster 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 per second. This is worked out by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). 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 get to the maximum fill rate.