Radeon HD 4870 X2 vs Radeon R9 M390X

Intro

Compare those specs to the Radeon R9 M390X, which features GPU core speed of 723 MHz, and 4096 MB of GDDR5 memory running at 1250 MHz through a 256-bit bus. It also is comprised of 2048 SPUs, 128 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M390X		125 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 225 Watts (180%)

Memory Bandwidth

Theoretically, the Radeon HD 4870 X2 should perform much faster than the Radeon R9 M390X overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon R9 M390X		160000 MB/sec
	Difference: 70400 (44%)

Texel Rate

The Radeon R9 M390X should be much (more or less 54%) more effective at texture filtering than the Radeon HD 4870 X2. (explain)

Radeon R9 M390X		92544 Mtexels/sec
Radeon HD 4870 X2		60000 Mtexels/sec
	Difference: 32544 (54%)

Pixel Rate

The Radeon HD 4870 X2 is a bit (about 4%) better at AA than the Radeon R9 M390X, and will be able to handle higher screen resolutions while still performing well. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon R9 M390X		23136 Mpixels/sec
	Difference: 864 (4%)

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 data (counted in MB per second) that can be transferred past the external memory interface within a second. The number is worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The better this number, 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 amount of pixels the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the clock 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 is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.