Radeon HD 4890 2GB vs Radeon R9 285

Intro

Compare that to the Radeon R9 285, which comes with a clock frequency of 918 MHz and a GDDR5 memory speed of 1375 MHz. It also uses a 256-bit bus, and makes use of a 28 nm design. It is made up of 1792 SPUs, 112 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

As far as performance goes, the Radeon R9 285 should in theory be quite a bit superior to the Radeon HD 4890 2GB in general. (explain)

Radeon R9 285		176000 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 51200 (41%)

Texel Rate

The Radeon R9 285 is much (more or less 157%) better at AF than the Radeon HD 4890 2GB. (explain)

Radeon R9 285		102816 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 62816 (157%)

Pixel Rate

If using a high resolution is important to you, then the Radeon R9 285 is the winner, and very much so. (explain)

Radeon R9 285		29376 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 13376 (84%)

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 (in units of MB per second) that can be transported past 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 must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

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