Radeon HD 4890 2GB vs Radeon R9 M385X

Intro

Compare that to the Radeon R9 M385X, which has GPU clock speed of 1100 MHz, and 4096 MB of GDDR5 memory set to run at 1500 MHz through a 128-bit bus. It also is comprised of 896 Stream Processors, 56 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 4890 2GB should in theory be quite a bit better than the Radeon R9 M385X in general. (explain)

Radeon HD 4890 2GB		124800 MB/sec
Radeon R9 M385X		96000 MB/sec
	Difference: 28800 (30%)

Texel Rate

The Radeon R9 M385X is much (more or less 54%) better at texture filtering than the Radeon HD 4890 2GB. (explain)

Radeon R9 M385X		61600 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 21600 (54%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon R9 M385X is a better choice, but it probably won't make a huge difference. (explain)

Radeon R9 M385X		17600 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 1600 (10%)

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 max amount of data (counted in MB per second) that can be moved across the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type memory, it must 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 anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also 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 of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.