Radeon HD 4870 2GB vs Radeon R9 390X 8G

Intro

Compare all that to the Radeon R9 390X 8G, which has a clock frequency of 1050 MHz and a GDDR5 memory frequency of 1500 MHz. It also makes use of a 512-bit bus, and uses a 28 nm design. It is comprised of 2816 SPUs, 176 Texture Address Units, and 64 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 2GB		150 Watts
Radeon R9 390X 8G		275 Watts
	Difference: 125 Watts (83%)

Memory Bandwidth

The Radeon R9 390X 8G, in theory, should be quite a bit faster than the Radeon HD 4870 2GB in general. (explain)

Radeon R9 390X 8G		384000 MB/sec
Radeon HD 4870 2GB		115200 MB/sec
	Difference: 268800 (233%)

Texel Rate

The Radeon R9 390X 8G should be a lot (about 516%) better at AF than the Radeon HD 4870 2GB. (explain)

Radeon R9 390X 8G		184800 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 154800 (516%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon R9 390X 8G is the winner, and very much so. (explain)

Radeon R9 390X 8G		67200 Mpixels/sec
Radeon HD 4870 2GB		12000 Mpixels/sec
	Difference: 55200 (460%)

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 (measured in megabytes per second) that can be moved past the external memory interface in one second. It is calculated by multiplying the card's interface width by its memory clock speed. If the card has DDR RAM, the result 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 AA, High Dynamic Range 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 calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.