Radeon HD 4850 1GB vs Radeon HD 6790

Intro

Compare all that to the Radeon HD 6790, which makes use of a 40 nm design. AMD has clocked the core speed at 840 MHz. The GDDR5 RAM is set to run at a speed of 1050 MHz on this model. It features 800 SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 1GB		110 Watts
Radeon HD 6790		150 Watts
	Difference: 40 Watts (36%)

Memory Bandwidth

The Radeon HD 6790, in theory, should perform quite a bit faster than the Radeon HD 4850 1GB overall. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 70848 (111%)

Texel Rate

The Radeon HD 6790 is a lot (approximately 34%) better at anisotropic filtering than the Radeon HD 4850 1GB. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 8600 (34%)

Pixel Rate

The Radeon HD 6790 will be quite a bit (about 34%) better at FSAA than the Radeon HD 4850 1GB, and will be able to handle higher screen resolutions better. (explain)

Radeon HD 6790		13440 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 3440 (34%)

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 (counted in MB per second) that can be transported across the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This figure is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the graphics 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 maximum amount of pixels the graphics card could possibly write to the 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 clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.