Radeon HD 7790 vs Radeon R9 M380

Intro

Compare those specifications to the Radeon R9 M380, which makes use of a 28 nm design. AMD has set the core frequency at 1000 MHz. The GDDR5 RAM runs at a frequency of 1500 MHz on this model. It features 640 SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Both cards have exactly the same memory bandwidth, so in theory they should have identical performance. (explain)

Texel Rate

The Radeon HD 7790 is a lot (approximately 40%) more effective at anisotropic filtering than the Radeon R9 M380. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon R9 M380		40000 Mtexels/sec
	Difference: 16000 (40%)

Pixel Rate

Both cards have exactly the same pixel fill rate, so in theory they should be equally good at at full screen anti-aliasing, and be able to handle the same resolutions. (explain)

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.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of information (measured in MB per second) that can be transported across the external memory interface in one second. It's calculated by multiplying the interface width by its memory speed. If the card has DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.