Radeon HD 7990 vs Radeon R9 M385X

Intro

Compare those specs to the Radeon R9 M385X, which makes use of a 28 nm design. AMD has clocked the core frequency at 1100 MHz. The GDDR5 RAM runs at a speed of 1500 MHz on this specific card. It features 896 SPUs along with 56 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 7990 should in theory perform quite a bit faster than the Radeon R9 M385X overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon R9 M385X		96000 MB/sec
	Difference: 480000 (500%)

Texel Rate

The Radeon HD 7990 should be much (about 295%) more effective at texture filtering than the Radeon R9 M385X. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon R9 M385X		61600 Mtexels/sec
	Difference: 181600 (295%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 7990 is a better choice, and very much so. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon R9 M385X		17600 Mpixels/sec
	Difference: 43200 (245%)

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 largest amount of information (counted in megabytes per second) that can be moved past the external memory interface in one second. The number is worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This number 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 graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

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