Radeon HD 4670 512MB vs Radeon R5 M255

Intro

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

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4670 512MB should in theory be much faster than the Radeon R5 M255 in general. (explain)

Radeon HD 4670 512MB		32000 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 16000 (100%)

Texel Rate

The Radeon HD 4670 512MB is quite a bit (approximately 28%) better at texture filtering than the Radeon R5 M255. (explain)

Radeon HD 4670 512MB		24000 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 5200 (28%)

Pixel Rate

The Radeon R5 M255 is much (about 25%) faster with regards to full screen anti-aliasing than the Radeon HD 4670 512MB, and should be able to handle higher resolutions while still performing well. (explain)

Radeon R5 M255		7520 Mpixels/sec
Radeon HD 4670 512MB		6000 Mpixels/sec
	Difference: 1520 (25%)

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 (measured in megabytes per second) that can be moved past the external memory interface in a second. It is calculated by multiplying the card's interface width by its memory speed. In the case of DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics card will be at 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 that the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also 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 of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.