Radeon HD 7870 vs Radeon R9 M390X

Intro

Compare all that to the Radeon R9 M390X, which features 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 features 2048 SPUs, 128 TAUs, 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 7870		175 Watts
	Difference: 50 Watts (40%)

Memory Bandwidth

Theoretically speaking, the Radeon R9 M390X should perform just a bit faster than the Radeon HD 7870 in general. (explain)

Radeon R9 M390X		160000 MB/sec
Radeon HD 7870		153600 MB/sec
	Difference: 6400 (4%)

Texel Rate

The Radeon R9 M390X will be a small bit (more or less 16%) more effective at AF than the Radeon HD 7870. (explain)

Radeon R9 M390X		92544 Mtexels/sec
Radeon HD 7870		80000 Mtexels/sec
	Difference: 12544 (16%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7870 is superior to the Radeon R9 M390X, by far. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon R9 M390X		23136 Mpixels/sec
	Difference: 8864 (38%)

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 (measured in MB per second) that can be transported past the external memory interface in a second. It's calculated by multiplying the interface width by its memory speed. If the card has DDR memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the 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 amount of pixels the video card could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the clock speed of the card. 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 many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.