Radeon HD 4830 512MB vs Radeon HD 6790

Intro

Compare those specifications to the Radeon HD 6790, which uses a 40 nm design. AMD has clocked the core frequency 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 TAUs and 16 ROPs.

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

As far as performance goes, the Radeon HD 6790 should in theory be quite a bit 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 will be quite a bit (more or less 83%) faster with regards to AF 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

The Radeon HD 6790 is quite a bit (more or less 46%) better at full screen anti-aliasing than the Radeon HD 4830 512MB, and also will be able to handle higher screen resolutions without losing too much performance. (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 maximum amount of data (counted in megabytes per second) that can be moved across the external memory interface within a second. The number is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied 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 better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the card's clock speed. 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 also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.