Radeon HD 3870 X2 512MB vs Radeon R9 280

Intro

Compare that to the Radeon R9 280, which comes with GPU clock speed of 933 MHz, and 3072 MB of GDDR5 memory set to run at 1250 MHz through a 384-bit bus. It also is comprised of 1792 Stream Processors, 112 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon R9 280 should in theory be quite a bit faster than the Radeon HD 3870 X2 512MB overall. (explain)

Radeon R9 280		240000 MB/sec
Radeon HD 3870 X2 512MB		115200 MB/sec
	Difference: 124800 (108%)

Texel Rate

The Radeon R9 280 should be much (approximately 296%) faster with regards to AF than the Radeon HD 3870 X2 512MB. (explain)

Radeon R9 280		104496 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 78096 (296%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon R9 280 is superior to the Radeon HD 3870 X2 512MB, not by a very large margin though. (explain)

Radeon R9 280		29856 Mpixels/sec
Radeon HD 3870 X2 512MB		26400 Mpixels/sec
	Difference: 3456 (13%)

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 maximum amount of information (in units of megabytes per second) that can be moved across the external memory interface within a second. It is worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better 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 number of texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.