Radeon HD 4830 512MB vs Radeon R5 M255

Intro

Compare that to the Radeon R5 M255, which makes use of a 28 nm design. AMD has set the core speed at 940 MHz. The DDR3 memory runs at a frequency of 1000 MHz on this particular model. It features 320 SPUs as well as 20 Texture Address Units and 8 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4830 512MB, in theory, should perform a lot faster than the Radeon R5 M255 in general. (explain)

Radeon HD 4830 512MB		57600 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 41600 (260%)

Texel Rate

The Radeon R5 M255 will be a small bit (more or less 2%) better at texture filtering than the Radeon HD 4830 512MB. (explain)

Radeon R5 M255		18800 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 400 (2%)

Pixel Rate

The Radeon HD 4830 512MB is a lot (more or less 22%) better at full screen anti-aliasing than the Radeon R5 M255, and also should be able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 4830 512MB		9200 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 1680 (22%)

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 (counted in MB 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 speed. If the card has DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This is calculated by multiplying the total number of texture units 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 per second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.