Radeon HD 4770 vs Radeon HD 4830 512MB

Intro

Compare all of that to the Radeon HD 4830 512MB, which makes use of a 55 nm design. AMD has clocked the core frequency at 575 MHz. The GDDR3 memory runs at a speed of 900 MHz on this model. It features 640(128x5) SPUs as well as 32 Texture Address Units and 16 ROPs.

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

Performance-wise, the Radeon HD 4830 512MB should theoretically be a bit better than the Radeon HD 4770 overall. (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 much (about 30%) faster with regards to texture 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 should be a lot (more or less 30%) more effective at AA than the Radeon HD 4830 512MB, and also will be capable of handling higher screen resolutions more effectively. (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: Bandwidth is the largest amount of information (counted in megabytes per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the bus width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, 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 is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the graphics 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 maximum number of pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.