Radeon HD 3870 1GB vs Radeon R9 M270X

Intro

Compare those specs to the Radeon R9 M270X, which comes with GPU clock speed of 725 MHz, and 2048 MB of GDDR5 RAM 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 memory bandwidth, so theoretically they should perform the same. (explain)

Texel Rate

The Radeon R9 M270X should be quite a bit (more or less 134%) better at texture filtering than the Radeon HD 3870 1GB. (explain)

Radeon R9 M270X		29000 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 16600 (134%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 3870 1GB is superior to the Radeon R9 M270X, though only just barely. (explain)

Radeon HD 3870 1GB		12400 Mpixels/sec
Radeon R9 M270X		11600 Mpixels/sec
	Difference: 800 (7%)

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 maximum amount of information (in units of MB per second) that can be transferred past the external memory interface within a second. It is calculated by multiplying the card's interface width by its memory speed. If the card has DDR RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, 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 texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines 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 fill rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.