Radeon HD 3870 1GB vs Radeon R9 M390X

Intro

Compare those specs to the Radeon R9 M390X, which comes with a clock frequency of 723 MHz and a GDDR5 memory speed of 1250 MHz. It also uses a 256-bit memory bus, and makes use of a 28 nm design. It is made up of 2048 SPUs, 128 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 1GB		106 Watts
Radeon R9 M390X		125 Watts
	Difference: 19 Watts (18%)

Memory Bandwidth

Theoretically speaking, the Radeon R9 M390X is 122% faster than the Radeon HD 3870 1GB in general, due to its greater data rate. (explain)

Radeon R9 M390X		160000 MB/sec
Radeon HD 3870 1GB		72000 MB/sec
	Difference: 88000 (122%)

Texel Rate

The Radeon R9 M390X should be quite a bit (approximately 646%) more effective at texture filtering than the Radeon HD 3870 1GB. (explain)

Radeon R9 M390X		92544 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 80144 (646%)

Pixel Rate

The Radeon R9 M390X should be much (about 87%) better at full screen anti-aliasing than the Radeon HD 3870 1GB, and will be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon R9 M390X		23136 Mpixels/sec
Radeon HD 3870 1GB		12400 Mpixels/sec
	Difference: 10736 (87%)

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 (in units of MB per second) that can be moved across the external memory interface in one second. It's calculated by multiplying the bus width by its memory speed. If the card has DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better 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 amount of texture map elements (texels) that can be processed in one second. This is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of 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 is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.