Radeon HD 7870 vs Radeon R9 M390X

Intro

Compare that to the Radeon R9 M390X, which comes with 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 Stream Processors, 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

Performance-wise, the Radeon R9 M390X should theoretically be a small bit better 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 is a bit (approximately 16%) faster with regards to 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 should be a lot (approximately 38%) faster with regards to FSAA than the Radeon R9 M390X, and also should be able to handle higher screen resolutions better. (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: Bandwidth is the max amount of information (in units of MB per second) that can be transferred across the external memory interface in a second. It is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant 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 reach the maximum fill rate.