Radeon HD 3870 1GB vs Radeon R7 250X 2GB

Intro

Compare all of that to the Radeon R7 250X 2GB, which features GPU clock speed of 1000 MHz, and 2048 MB of GDDR5 memory set to run at 1125 MHz through a 128-bit bus. It also features 640 Stream Processors, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R7 250X 2GB		95 Watts
Radeon HD 3870 1GB		106 Watts
	Difference: 11 Watts (12%)

Memory Bandwidth

Both cards have the exact same memory bandwidth, so in theory they should have identical performance. (explain)

Texel Rate

The Radeon R7 250X 2GB should be quite a bit (more or less 223%) more effective at anisotropic filtering than the Radeon HD 3870 1GB. (explain)

Radeon R7 250X 2GB		40000 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 27600 (223%)

Pixel Rate

The Radeon R7 250X 2GB will be a lot (about 29%) more effective at AA than the Radeon HD 3870 1GB, and will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon R7 250X 2GB		16000 Mpixels/sec
Radeon HD 3870 1GB		12400 Mpixels/sec
	Difference: 3600 (29%)

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 (counted in MB per second) that can be transferred across the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory speed. If the card has DDR type RAM, it should be multiplied by 2 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, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This number is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The better 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 a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.