Radeon HD 4830 1GB vs Radeon HD 6770 1GB

Intro

Compare that to the Radeon HD 6770 1GB, which makes use of a 40 nm design. AMD has set the core speed at 900 MHz. The GDDR5 RAM is set to run at a speed of 1050 MHz on this particular model. It features 800 SPUs along with 40 Texture Address Units 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

Theoretically speaking, the Radeon HD 6770 1GB will be 17% faster than the Radeon HD 4830 1GB in general, because of its higher data rate. (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 should be a lot (more or less 96%) faster with regards to AF 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 quite a bit (about 57%) more effective at full screen anti-aliasing than the Radeon HD 4830 1GB, and capable of handling higher resolutions better. (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 largest amount of data (in units of megabytes per second) that can be transferred over the external memory interface in a second. It is worked out by multiplying the bus width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, 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 number of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total texture units by the core speed of the chip. The better 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 graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.