Radeon HD 4870 2GB vs Radeon R9 M390X

Intro

Compare those specifications to the Radeon R9 M390X, which comes with GPU core speed of 723 MHz, and 4096 MB of GDDR5 memory set to run at 1250 MHz through a 256-bit bus. It also is comprised of 2048 Stream Processors, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M390X		125 Watts
Radeon HD 4870 2GB		150 Watts
	Difference: 25 Watts (20%)

Memory Bandwidth

Theoretically speaking, the Radeon R9 M390X is 39% faster than the Radeon HD 4870 2GB in general, because of its greater bandwidth. (explain)

Radeon R9 M390X		160000 MB/sec
Radeon HD 4870 2GB		115200 MB/sec
	Difference: 44800 (39%)

Texel Rate

The Radeon R9 M390X is a lot (approximately 208%) better at AF than the Radeon HD 4870 2GB. (explain)

Radeon R9 M390X		92544 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 62544 (208%)

Pixel Rate

The Radeon R9 M390X should be a lot (about 93%) more effective at FSAA than the Radeon HD 4870 2GB, and also should be capable of handling higher screen resolutions more effectively. (explain)

Radeon R9 M390X		23136 Mpixels/sec
Radeon HD 4870 2GB		12000 Mpixels/sec
	Difference: 11136 (93%)

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: Bandwidth is the max amount of information (counted in megabytes per second) that can be transported across the external memory interface in one second. It's worked out by multiplying the interface width by the speed of its memory. If the card has DDR type RAM, it should 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 number of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the video 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 the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.