Radeon HD 4830 1GB vs Radeon HD 6770 1GB

Intro

Compare all of that to the Radeon HD 6770 1GB, which uses a 40 nm design. AMD has clocked the core speed at 900 MHz. The GDDR5 RAM runs at a frequency of 1050 MHz on this card. It features 800 SPUs along with 40 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 1GB		95 Watts
Radeon HD 6770 1GB		108 Watts
	Difference: 13 Watts (14%)

Memory Bandwidth

Performance-wise, the Radeon HD 6770 1GB should theoretically be a little bit better than the Radeon HD 4830 1GB overall. (explain)

Radeon HD 6770 1GB		67200 MB/sec
Radeon HD 4830 1GB		57600 MB/sec
	Difference: 9600 (17%)

Texel Rate

The Radeon HD 6770 1GB is much (about 96%) faster with regards to anisotropic filtering than the Radeon HD 4830 1GB. (explain)

Radeon HD 6770 1GB		36000 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 17600 (96%)

Pixel Rate

The Radeon HD 6770 1GB should be a lot (more or less 57%) more effective at AA than the Radeon HD 4830 1GB, and will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 6770 1GB		14400 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 5200 (57%)

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 maximum amount of data (in units of megabytes per second) that can be transported past the external memory interface within a second. The number is calculated by multiplying the card's interface width by its memory speed. In the case of DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.