Radeon HD 4870 2GB vs Radeon HD 4890 2GB

Intro

Compare those specs to the Radeon HD 4890 2GB, which comes with a GPU core clock speed of 1000 MHz, and 2048 MB of GDDR5 RAM running at 975 MHz through a 256-bit bus. It also features 800(160x5) Stream Processors, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 2GB		150 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 40 Watts (27%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4890 2GB will be 8% quicker than the Radeon HD 4870 2GB in general, due to its higher data rate. (explain)

Radeon HD 4890 2GB		124800 MB/sec
Radeon HD 4870 2GB		115200 MB/sec
	Difference: 9600 (8%)

Texel Rate

The Radeon HD 4890 2GB is a lot (more or less 33%) more effective at anisotropic filtering than the Radeon HD 4870 2GB. (explain)

Radeon HD 4890 2GB		40000 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 10000 (33%)

Pixel Rate

The Radeon HD 4890 2GB will be much (more or less 33%) faster with regards to full screen anti-aliasing than the Radeon HD 4870 2GB, and also should be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 4890 2GB		16000 Mpixels/sec
Radeon HD 4870 2GB		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 information (measured in megabytes per second) that can be moved across the external memory interface in a second. The number is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better 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 number is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the video 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 most pixels that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.