Radeon HD 4830 512MB vs Radeon HD 6870

Intro

Compare those specs to the Radeon HD 6870, which uses a 40 nm design. AMD has clocked the core speed at 900 MHz. The GDDR5 memory is set to run at a frequency of 1050 MHz on this model. It features 1120 SPUs as well as 56 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
Radeon HD 6870		151 Watts
	Difference: 56 Watts (59%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6870 should be a lot faster than the Radeon HD 4830 512MB overall. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 76800 (133%)

Texel Rate

The Radeon HD 6870 will be quite a bit (more or less 174%) better at anisotropic filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 32000 (174%)

Pixel Rate

The Radeon HD 6870 should be a lot (more or less 213%) better at full screen anti-aliasing than the Radeon HD 4830 512MB, and also should be able to handle higher screen resolutions better. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 19600 (213%)

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 (counted in MB per second) that can be transferred over the external memory interface within a second. It's worked out by multiplying the bus width by the speed of its memory. If the card has DDR memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.