Radeon HD 4870 512MB vs Radeon R9 390 8G

Intro

Compare those specifications to the Radeon R9 390 8G, which has GPU clock speed of 1000 MHz, and 8192 MB of GDDR5 memory set to run at 1500 MHz through a 512-bit bus. It also features 2560 Stream Processors, 160 Texture Address Units, and 64 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 512MB		150 Watts
Radeon R9 390 8G		275 Watts
	Difference: 125 Watts (83%)

Memory Bandwidth

Theoretically speaking, the Radeon R9 390 8G should be a lot faster than the Radeon HD 4870 512MB in general. (explain)

Radeon R9 390 8G		384000 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 268800 (233%)

Texel Rate

The Radeon R9 390 8G is a lot (approximately 433%) more effective at texture filtering than the Radeon HD 4870 512MB. (explain)

Radeon R9 390 8G		160000 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 130000 (433%)

Pixel Rate

The Radeon R9 390 8G will be quite a bit (about 433%) better at anti-aliasing than the Radeon HD 4870 512MB, and capable of handling higher screen resolutions better. (explain)

Radeon R9 390 8G		64000 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 52000 (433%)

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 largest amount of data (counted in megabytes per second) that can be moved across the external memory interface within a second. It's worked out by multiplying the interface width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.