Radeon HD 4790 vs Radeon HD 5850

Intro

Compare all that to the Radeon HD 5850, which uses a 40 nm design. ATi has set the core frequency at 725 MHz. The GDDR5 memory is set to run at a speed of 1000 MHz on this card. It features 1440(288x5) SPUs along with 72 Texture Address Units and 32 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 5850 should be much faster than the Radeon HD 4790 in general. (explain)

Radeon HD 5850		128000 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 25600 (25%)

Texel Rate

The Radeon HD 5850 is a lot (approximately 172%) more effective at anisotropic filtering than the Radeon HD 4790. (explain)

Radeon HD 5850		52200 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 33000 (172%)

Pixel Rate

The Radeon HD 5850 is much (approximately 142%) better at full screen anti-aliasing than the Radeon HD 4790, and should be capable of handling higher screen resolutions better. (explain)

Radeon HD 5850		23200 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 13600 (142%)

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 maximum amount of data (in units of MB per second) that can be transported past the external memory interface in one second. The number is worked out by multiplying the bus width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total texture units of the card 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 per second.

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