Radeon HD 4830 1GB vs Radeon HD 4890 1GB

Intro

Compare those specifications to the Radeon HD 4890 1GB, which makes use of a 55 nm design. AMD has set the core frequency at 1000 MHz. The GDDR5 RAM works at a frequency of 975 MHz on this particular model. It features 800(160x5) SPUs as well as 40 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 4830 1GB		95 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 95 Watts (100%)

Memory Bandwidth

Theoretically, the Radeon HD 4890 1GB should perform quite a bit faster than the Radeon HD 4830 1GB in general. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 4830 1GB		57600 MB/sec
	Difference: 67200 (117%)

Texel Rate

The Radeon HD 4890 1GB is much (about 117%) faster with regards to texture filtering than the Radeon HD 4830 1GB. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 21600 (117%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 4890 1GB is the winner, by far. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 6800 (74%)

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 largest amount of information (measured in MB per second) that can be transported over the external memory interface in one second. It is calculated by multiplying the bus width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total 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 applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.