Radeon HD 4830 512MB vs Radeon HD 7850

Intro

Compare all that to the Radeon HD 7850, which features clock speeds of 860 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 RAM. It features 1024 SPUs as well as 64 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
Radeon HD 7850		130 Watts
	Difference: 35 Watts (37%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7850 should theoretically be quite a bit superior to the Radeon HD 4830 512MB overall. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 96000 (167%)

Texel Rate

The Radeon HD 7850 will be much (about 199%) more effective at texture filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 36640 (199%)

Pixel Rate

The Radeon HD 7850 is quite a bit (about 199%) better at anti-aliasing than the Radeon HD 4830 512MB, and also will be able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 18320 (199%)

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 largest amount of data (counted in megabytes per second) that can be transferred past the external memory interface in a second. It is calculated by multiplying the card's interface width by its memory clock speed. If the card has DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high 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 number of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the 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 graphics card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.