Radeon HD 4870 1GB vs Radeon HD 4890 1GB

Intro

Compare those specs to the Radeon HD 4890 1GB, which uses a 55 nm design. AMD has set the core speed at 1000 MHz. The GDDR5 RAM runs at a frequency of 975 MHz on this card. It features 800(160x5) SPUs along with 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 4870 1GB		150 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 40 Watts (27%)

Memory Bandwidth

The Radeon HD 4890 1GB should in theory be a little bit faster than the Radeon HD 4870 1GB in general. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 4870 1GB		115200 MB/sec
	Difference: 9600 (8%)

Texel Rate

The Radeon HD 4890 1GB is much (more or less 33%) faster with regards to AF than the Radeon HD 4870 1GB. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 10000 (33%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 4890 1GB is superior to the Radeon HD 4870 1GB, by far. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 4000 (33%)

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 moved over 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, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, 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 are applied in one second. This is worked out by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.