Radeon HD 4870 2GB vs Radeon R9 380 4G

Intro

Compare all of that to the Radeon R9 380 4G, which has a clock frequency of 970 MHz and a GDDR5 memory speed of 1425 MHz. It also features a 256-bit memory bus, and uses a 28 nm design. It is comprised of 1792 SPUs, 112 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 2GB		150 Watts
Radeon R9 380 4G		190 Watts
	Difference: 40 Watts (27%)

Memory Bandwidth

In theory, the Radeon R9 380 4G is 58% quicker than the Radeon HD 4870 2GB in general, due to its greater bandwidth. (explain)

Radeon R9 380 4G		182400 MB/sec
Radeon HD 4870 2GB		115200 MB/sec
	Difference: 67200 (58%)

Texel Rate

The Radeon R9 380 4G should be a lot (approximately 262%) more effective at texture filtering than the Radeon HD 4870 2GB. (explain)

Radeon R9 380 4G		108640 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 78640 (262%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon R9 380 4G is a better choice, by a large margin. (explain)

Radeon R9 380 4G		31040 Mpixels/sec
Radeon HD 4870 2GB		12000 Mpixels/sec
	Difference: 19040 (159%)

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 data (measured in megabytes per second) that can be moved across the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory speed. In the case of DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the core 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 many 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.