Radeon HD 4870 X2 vs Radeon R9 M390X

Intro

Compare those specs to the Radeon R9 M390X, which features GPU clock 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 Stream Processors, 128 Texture Address Units, 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

The Radeon HD 4870 X2, in theory, should be quite a bit 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 a lot (about 54%) better at AF 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 will be a bit (about 4%) more effective at FSAA than the Radeon R9 M390X, and also should be able to handle higher resolutions without slowing down too much. (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: Memory bandwidth is the largest amount of information (in units of MB per second) that can be moved across the external memory interface in a second. It is calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, 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 number of texture map elements (texels) that are applied in one second. This is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the clock speed of the card. 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 output rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.