Radeon HD 3870 512MB vs Radeon R9 M275X

Intro

Compare those specs to the Radeon R9 M275X, which uses a 28 nm design. AMD has clocked the core frequency at 900 MHz. The GDDR5 memory is set to run at a speed of 1125 MHz on this particular card. It features 640 SPUs along with 40 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M275X		50 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 56 Watts (112%)

Memory Bandwidth

The Radeon R9 M275X, in theory, should perform a lot faster than the Radeon HD 3870 512MB overall. (explain)

Radeon R9 M275X		72000 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 14400 (25%)

Texel Rate

The Radeon R9 M275X will be much (more or less 190%) more effective at anisotropic filtering than the Radeon HD 3870 512MB. (explain)

Radeon R9 M275X		36000 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 23600 (190%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon R9 M275X is the winner, though only just barely. (explain)

Radeon R9 M275X		14400 Mpixels/sec
Radeon HD 3870 512MB		12400 Mpixels/sec
	Difference: 2000 (16%)

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: Bandwidth is the maximum amount of data (measured in MB per second) that can be transported past the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory speed. In the case of DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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