Radeon HD 4790 vs Radeon R9 M385X

Intro

Compare that to the Radeon R9 M385X, which makes use of a 28 nm design. AMD has clocked the core frequency at 1100 MHz. The GDDR5 memory is set to run at a speed of 1500 MHz on this card. It features 896 SPUs along with 56 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon HD 4790 should in theory be a small bit better than the Radeon R9 M385X overall. (explain)

Radeon HD 4790		102400 MB/sec
Radeon R9 M385X		96000 MB/sec
	Difference: 6400 (7%)

Texel Rate

The Radeon R9 M385X is a lot (approximately 221%) better at AF than the Radeon HD 4790. (explain)

Radeon R9 M385X		61600 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 42400 (221%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon R9 M385X is the winner, and very much so. (explain)

Radeon R9 M385X		17600 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 8000 (83%)

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 maximum amount of information (counted 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 RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This is worked out by multiplying the total 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 in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record 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 clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.