Radeon HD 4870 X2 vs Radeon R9 M385X

Intro

Compare all that to the Radeon R9 M385X, which comes with core clock speeds of 1100 MHz on the GPU, and 1500 MHz on the 4096 MB of GDDR5 memory. It features 896 SPUs along with 56 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 4870 X2 is 140% faster than the Radeon R9 M385X in general, due to its higher data rate. (explain)

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

Texel Rate

The Radeon R9 M385X should be a bit (approximately 3%) better at texture 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

The Radeon HD 4870 X2 should be much (more or less 36%) better at anti-aliasing than the Radeon R9 M385X, and also capable of handling higher screen resolutions more effectively. (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 maximum amount of information (in units of megabytes per second) that can be moved over the external memory interface within a second. The number is calculated by multiplying the interface width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units 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 rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.