Radeon HD 4890 1GB vs Radeon R9 M395X

Intro

Compare those specifications to the Radeon R9 M395X, which features clock speeds of 723 MHz on the GPU, and 1250 MHz on the 4096 MB of GDDR5 RAM. It features 2048 SPUs along with 128 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M395X		125 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 65 Watts (52%)

Memory Bandwidth

Theoretically speaking, the Radeon R9 M395X will be 28% faster than the Radeon HD 4890 1GB overall, due to its higher bandwidth. (explain)

Radeon R9 M395X		160000 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 35200 (28%)

Texel Rate

The Radeon R9 M395X will be much (approximately 131%) better at texture filtering than the Radeon HD 4890 1GB. (explain)

Radeon R9 M395X		92544 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 52544 (131%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon R9 M395X is the winner, by a large margin. (explain)

Radeon R9 M395X		23136 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 7136 (45%)

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 maximum amount of information (counted in megabytes per second) that can be transferred past the external memory interface within a second. The number is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's 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 in one second. This figure is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.