Radeon HD 4890 2GB vs Radeon HD 5870

Intro

Compare those specs to the Radeon HD 5870, which comes with clock speeds of 850 MHz on the GPU, and 1200 MHz on the 1024 MB of GDDR5 RAM. It features 1600(320x5) SPUs along with 80 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5870		188 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 2 Watts (1%)

Memory Bandwidth

The Radeon HD 5870 should theoretically perform quite a bit faster than the Radeon HD 4890 2GB overall. (explain)

Radeon HD 5870		153600 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 28800 (23%)

Texel Rate

The Radeon HD 5870 should be a lot (approximately 70%) faster with regards to anisotropic filtering than the Radeon HD 4890 2GB. (explain)

Radeon HD 5870		68000 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 28000 (70%)

Pixel Rate

The Radeon HD 5870 is quite a bit (approximately 70%) better at AA than the Radeon HD 4890 2GB, and capable of handling higher screen resolutions more effectively. (explain)

Radeon HD 5870		27200 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 11200 (70%)

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 megabytes per second) that can be transferred across the external memory interface within a second. The number is worked out by multiplying the interface width by the speed of its memory. In the case of DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better 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 per second. This number is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better 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 that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.