Radeon HD 4790 vs Radeon HD 6790

Intro

Compare that to the Radeon HD 6790, which uses 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 specific model. It features 800 SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically, the Radeon HD 6790 should be quite a bit faster than the Radeon HD 4790 overall. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 32000 (31%)

Texel Rate

The Radeon HD 6790 will be a lot (approximately 75%) faster with regards to AF than the Radeon HD 4790. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 14400 (75%)

Pixel Rate

The Radeon HD 6790 will be quite a bit (more or less 40%) more effective at anti-aliasing than the Radeon HD 4790, and also should be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 6790		13440 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 3840 (40%)

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 information (measured in MB per second) that can be transferred over the external memory interface in a second. The number is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen 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 number of texture units by the core clock speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

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