Radeon HD 4830 512MB vs Radeon HD 6790

Intro

Compare that to the Radeon HD 6790, which features a clock speed of 840 MHz and a GDDR5 memory frequency of 1050 MHz. It also features a 256-bit memory bus, and makes use of a 40 nm design. It is made up of 800 SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
Radeon HD 6790		150 Watts
	Difference: 55 Watts (58%)

Memory Bandwidth

Performance-wise, the Radeon HD 6790 should theoretically be much better than the Radeon HD 4830 512MB in general. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 76800 (133%)

Texel Rate

The Radeon HD 6790 is quite a bit (approximately 83%) more effective at texture filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 15200 (83%)

Pixel Rate

If using a high resolution 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 4830 512MB		9200 Mpixels/sec
	Difference: 4240 (46%)

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 largest amount of data (measured in megabytes per second) that can be transported over the external memory interface in a second. It is calculated by multiplying the bus width by its memory speed. In the case of DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This figure is worked out 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 card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the core 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 output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.