Radeon HD 4870 2GB vs Radeon HD 4890 1GB

Intro

Compare all that to the Radeon HD 4890 1GB, which uses a 55 nm design. AMD has clocked the core speed at 1000 MHz. The GDDR5 RAM works 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

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 2GB		150 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 40 Watts (27%)

Memory Bandwidth

Performance-wise, the Radeon HD 4890 1GB should in theory be just a bit superior to the Radeon HD 4870 2GB in general. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 4870 2GB		115200 MB/sec
	Difference: 9600 (8%)

Texel Rate

The Radeon HD 4890 1GB should be a lot (more or less 33%) better at texture filtering than the Radeon HD 4870 2GB. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 10000 (33%)

Pixel Rate

The Radeon HD 4890 1GB will be quite a bit (approximately 33%) better at AA than the Radeon HD 4870 2GB, and capable of handling higher resolutions more effectively. (explain)

Radeon HD 4890 1GB		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: Memory bandwidth is the maximum amount of information (measured in MB per second) that can be transferred across the external memory interface in a second. The number is worked out by multiplying the card's bus width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.