Radeon HD 7770 vs Radeon R9 M265X

Intro

Compare all of that to the Radeon R9 M265X, which has a GPU core clock speed of 575 MHz, and 2048 MB of GDDR5 memory running at 1125 MHz through a 128-bit bus. It also is made up of 640 SPUs, 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 bandwidth, so theoretically they should perform the same. (explain)

Texel Rate

The Radeon HD 7770 should be much (approximately 74%) better at anisotropic filtering than the Radeon R9 M265X. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon R9 M265X		23000 Mtexels/sec
	Difference: 17000 (74%)

Pixel Rate

The Radeon HD 7770 will be a lot (about 74%) faster with regards to AA than the Radeon R9 M265X, and will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon R9 M265X		9200 Mpixels/sec
	Difference: 6800 (74%)

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 maximum amount of information (counted in megabytes per second) that can be transported across the external memory interface in one second. It's calculated by multiplying the bus 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 ANOTHER 2x. 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 amount of texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total texture units by the core 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 per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.