Radeon HD 3870 X2 512MB vs Radeon R9 285

Intro

Compare all that to the Radeon R9 285, which features a core clock speed 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 features 1792 SPUs, 112 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon R9 285 should in theory be quite a bit superior to the Radeon HD 3870 X2 512MB overall. (explain)

Radeon R9 285		176000 MB/sec
Radeon HD 3870 X2 512MB		115200 MB/sec
	Difference: 60800 (53%)

Texel Rate

The Radeon R9 285 should be much (about 289%) better at AF than the Radeon HD 3870 X2 512MB. (explain)

Radeon R9 285		102816 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 76416 (289%)

Pixel Rate

The Radeon R9 285 will be just a bit (more or less 11%) faster with regards to full screen anti-aliasing than the Radeon HD 3870 X2 512MB, and should be capable of handling higher resolutions better. (explain)

Radeon R9 285		29376 Mpixels/sec
Radeon HD 3870 X2 512MB		26400 Mpixels/sec
	Difference: 2976 (11%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of information (counted in MB per second) that can be transported across the external memory interface in a second. The number is calculated by multiplying the interface width by the speed of its memory. If it uses DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card could 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 ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.