Radeon HD 4870 2GB vs Radeon R9 M270X

Intro

Compare those specifications to the Radeon R9 M270X, which has GPU clock speed of 725 MHz, and 2048 MB of GDDR5 memory running at 1125 MHz through a 128-bit bus. It also features 640 Stream Processors, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 4870 2GB should be 60% quicker than the Radeon R9 M270X overall, due to its greater data rate. (explain)

Radeon HD 4870 2GB		115200 MB/sec
Radeon R9 M270X		72000 MB/sec
	Difference: 43200 (60%)

Texel Rate

The Radeon HD 4870 2GB is a bit (about 3%) faster with regards to texture filtering than the Radeon R9 M270X. (explain)

Radeon HD 4870 2GB		30000 Mtexels/sec
Radeon R9 M270X		29000 Mtexels/sec
	Difference: 1000 (3%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 4870 2GB is the winner, but only just. (explain)

Radeon HD 4870 2GB		12000 Mpixels/sec
Radeon R9 M270X		11600 Mpixels/sec
	Difference: 400 (3%)

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 megabytes per second) that can be moved past the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory speed. In the case of DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the video 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 chip can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.