Radeon HD 7970 vs Radeon R5 M255

Intro

Compare those specs to the Radeon R5 M255, which has GPU clock speed of 940 MHz, and 2048 MB of DDR3 memory set to run at 1000 MHz through a 64-bit bus. It also is comprised of 320 SPUs, 20 TAUs, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon HD 7970 should theoretically be quite a bit better than the Radeon R5 M255 in general. (explain)

Radeon HD 7970		264000 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 248000 (1550%)

Texel Rate

The Radeon HD 7970 is much (approximately 530%) faster with regards to texture filtering than the Radeon R5 M255. (explain)

Radeon HD 7970		118400 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 99600 (530%)

Pixel Rate

The Radeon HD 7970 should be a lot (more or less 294%) faster with regards to AA than the Radeon R5 M255, and able to handle higher resolutions while still performing well. (explain)

Radeon HD 7970		29600 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 22080 (294%)

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 largest amount of data (measured in MB per second) that can be transferred over the external memory interface in one second. It's calculated by multiplying the interface width by the speed of its memory. If the card has DDR memory, the result 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 AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This is worked out by multiplying the total number 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 processed in one second.

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