Radeon HD 7790 vs Radeon R5 M255

Intro

Compare all of that to the Radeon R5 M255, which has a core clock speed of 940 MHz and a DDR3 memory speed of 1000 MHz. It also makes use of a 64-bit bus, and uses a 28 nm design. It features 320 SPUs, 20 TAUs, and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon HD 7790 should theoretically be quite a bit better than the Radeon R5 M255 overall. (explain)

Radeon HD 7790		96000 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 80000 (500%)

Texel Rate

The Radeon HD 7790 should be quite a bit (more or less 198%) faster with regards to texture filtering than the Radeon R5 M255. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 37200 (198%)

Pixel Rate

The Radeon HD 7790 is quite a bit (approximately 113%) more effective at FSAA than the Radeon R5 M255, and should be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 7790		16000 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 8480 (113%)

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: Memory bandwidth is the largest amount of data (in units of MB per second) that can be transported over the external memory interface in one second. The number is calculated by multiplying the bus width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The better this number, 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 amount of pixels the video card could possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.