Radeon HD 7870 vs Radeon R9 M390X

Intro

Compare all that to the Radeon R9 M390X, which has GPU clock speed of 723 MHz, and 4096 MB of GDDR5 RAM running at 1250 MHz through a 256-bit bus. It also is comprised of 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 be a little 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 should be just a bit (more or less 16%) better at texture filtering than the Radeon HD 7870. (explain)

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

Pixel Rate

The Radeon HD 7870 is quite a bit (approximately 38%) more effective at full screen anti-aliasing than the Radeon R9 M390X, and also should be able to handle higher screen resolutions more effectively. (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 information (measured in MB per second) that can be transported over the external memory interface within a second. It is worked out by multiplying the 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 higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.