Radeon HD 4870 512MB vs Radeon R7 250X 2GB

Intro

Compare that to the Radeon R7 250X 2GB, which features a clock speed of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also makes use of a 128-bit memory bus, and uses a 28 nm design. It features 640 SPUs, 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 4870 512MB		150 Watts
	Difference: 55 Watts (58%)

Memory Bandwidth

In theory, the Radeon HD 4870 512MB should be 60% quicker than the Radeon R7 250X 2GB in general, due to its greater data rate. (explain)

Radeon HD 4870 512MB		115200 MB/sec
Radeon R7 250X 2GB		72000 MB/sec
	Difference: 43200 (60%)

Texel Rate

The Radeon R7 250X 2GB will be a lot (about 33%) more effective at AF than the Radeon HD 4870 512MB. (explain)

Radeon R7 250X 2GB		40000 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 10000 (33%)

Pixel Rate

The Radeon R7 250X 2GB will be quite a bit (about 33%) better at anti-aliasing than the Radeon HD 4870 512MB, and also should be capable of handling higher resolutions more effectively. (explain)

Radeon R7 250X 2GB		16000 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 4000 (33%)

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 data (counted in megabytes per second) that can be transported across the external memory interface in one second. It is worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This number is worked out by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to its local memory per 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 - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.