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 speed at 840 MHz. The GDDR5 RAM is set to run at a frequency of 1050 MHz on this model. It features 800 SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, 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 quite a bit (more or less 75%) faster with regards to texture filtering than the Radeon HD 4790. (explain)

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

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 6790 is a better choice, by a large margin. (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 max amount of information (in units of megabytes per second) that can be moved over the external memory interface within a second. It's calculated by multiplying the bus width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's 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 texture map elements (texels) that are applied in one second. This figure is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.