Radeon HD 4870 X2 vs Radeon R9 M385X

Intro

Compare those specs 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 works at a speed of 1500 MHz on this model. 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

Theoretically speaking, the Radeon HD 4870 X2 should perform quite a bit 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 is just a bit (approximately 3%) more effective 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 quite a bit (more or less 36%) better at AA than the Radeon R9 M385X, and will be capable of handling higher resolutions while still performing well. (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 past the external memory interface in a second. It is worked out by multiplying the interface width by the speed of its memory. If the card has DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called 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, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.