Radeon HD 4870 X2 vs Radeon R7 250X

Intro

Compare those specs to the Radeon R7 250X, which comes with a clock frequency of 1000 MHz and a GDDR5 memory speed of 1125 MHz. It also makes use of a 128-bit bus, and makes use of a 28 nm design. It is made up of 640 SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R7 250X		95 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 255 Watts (268%)

Memory Bandwidth

Performance-wise, the Radeon HD 4870 X2 should theoretically be much better than the Radeon R7 250X overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon R7 250X		72000 MB/sec
	Difference: 158400 (220%)

Texel Rate

The Radeon HD 4870 X2 will be quite a bit (more or less 50%) more effective at texture filtering than the Radeon R7 250X. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon R7 250X		40000 Mtexels/sec
	Difference: 20000 (50%)

Pixel Rate

The Radeon HD 4870 X2 is much (about 50%) faster with regards to AA than the Radeon R7 250X, and capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon R7 250X		16000 Mpixels/sec
	Difference: 8000 (50%)

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: Memory bandwidth is the largest amount of information (counted in MB per second) that can be transferred past the external memory interface in one second. The number is calculated by multiplying the interface width by its memory speed. If it uses DDR type RAM, it must be multiplied by 2 again. If 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 can be applied in one second. This number 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 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 that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.