GeForce GT 420 vs Radeon HD 4790

Intro

Compare all of that to the Radeon HD 4790, which comes with a clock frequency of 600 MHz and a GDDR5 memory speed of 800 MHz. It also uses a 256-bit bus, and uses a 55 nm design. It is comprised of 640(128x5) SPUs, 32 TAUs, and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 4790 should in theory be a lot better than the GeForce GT 420 overall. (explain)

Radeon HD 4790		102400 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 73600 (256%)

Texel Rate

The Radeon HD 4790 is much (more or less 243%) more effective at AF than the GeForce GT 420. (explain)

Radeon HD 4790		19200 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 13600 (243%)

Pixel Rate

The Radeon HD 4790 should be a lot (approximately 243%) more effective at FSAA than the GeForce GT 420, and also should be able to handle higher screen resolutions better. (explain)

Radeon HD 4790		9600 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 6800 (243%)

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 MB per second) that can be moved over the external memory interface within a second. The number is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed 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 higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill 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 get to the max fill rate.