Radeon HD 4870 1GB vs Radeon R7 250X

Intro

Compare those specifications to the Radeon R7 250X, which features a clock frequency of 1000 MHz and a GDDR5 memory speed of 1125 MHz. It also features a 128-bit memory bus, and uses a 28 nm design. It is comprised of 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		95 Watts
Radeon HD 4870 1GB		150 Watts
	Difference: 55 Watts (58%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4870 1GB will be 60% quicker than the Radeon R7 250X overall, because of its greater bandwidth. (explain)

Radeon HD 4870 1GB		115200 MB/sec
Radeon R7 250X		72000 MB/sec
	Difference: 43200 (60%)

Texel Rate

The Radeon R7 250X will be much (about 33%) faster with regards to anisotropic filtering than the Radeon HD 4870 1GB. (explain)

Radeon R7 250X		40000 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 10000 (33%)

Pixel Rate

The Radeon R7 250X should be a lot (more or less 33%) more effective at full screen anti-aliasing than the Radeon HD 4870 1GB, and capable of handling higher resolutions while still performing well. (explain)

Radeon R7 250X		16000 Mpixels/sec
Radeon HD 4870 1GB		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 max amount of information (in units of megabytes per second) that can be moved across the external memory interface within a second. The number is worked out by multiplying the bus width by the speed of its memory. If it uses DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better 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 number of texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total number of texture units of the card by the core clock 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 maximum number of pixels that the graphics chip could possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount 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 drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.