Radeon HD 4870 X2 vs Radeon R9 M385X

Intro

Compare all of that to the Radeon R9 M385X, which makes use of a 28 nm design. AMD has set the core frequency at 1100 MHz. The GDDR5 RAM runs at a frequency of 1500 MHz on this specific model. It features 896 SPUs as well as 56 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically, the Radeon HD 4870 X2 should be a lot faster than the Radeon R9 M385X overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon R9 M385X		96000 MB/sec
	Difference: 134400 (140%)

Texel Rate

The Radeon R9 M385X will be a bit (approximately 3%) more effective at anisotropic filtering than the Radeon HD 4870 X2. (explain)

Radeon R9 M385X		61600 Mtexels/sec
Radeon HD 4870 X2		60000 Mtexels/sec
	Difference: 1600 (3%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 4870 X2 is the winner, by far. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon R9 M385X		17600 Mpixels/sec
	Difference: 6400 (36%)

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 megabytes per second) that can be transferred over the external memory interface within a second. It's worked out by multiplying the interface width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. 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 can be processed per second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.