Radeon HD 4770 vs Radeon HD 4830 512MB

Intro

Compare all of that to the Radeon HD 4830 512MB, which has core clock speeds of 575 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 memory. It features 640(128x5) SPUs as well as 32 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 4830 512MB		95 Watts
	Difference: 15 Watts (19%)

Memory Bandwidth

Theoretically, the Radeon HD 4830 512MB should perform a bit faster than the Radeon HD 4770 in general. (explain)

Radeon HD 4830 512MB		57600 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 6400 (13%)

Texel Rate

The Radeon HD 4770 should be quite a bit (more or less 30%) more effective at anisotropic filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 4770		24000 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 5600 (30%)

Pixel Rate

The Radeon HD 4770 will be much (about 30%) better at anti-aliasing than the Radeon HD 4830 512MB, and will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 4770		12000 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 2800 (30%)

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 information (measured in MB per second) that can be transferred over the external memory interface within a second. The number is worked out by multiplying the bus width by its memory speed. If the card has DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster 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 per second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the card will be at handling 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 could possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the core 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 output rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.