Radeon HD 4850 X2 512MB vs Radeon R9 390 8G

Intro

Compare that to the Radeon R9 390 8G, which makes use of a 28 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 RAM works at a speed of 1500 MHz on this particular model. It features 2560 SPUs as well as 160 Texture Address Units and 64 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 X2 512MB		250 Watts
Radeon R9 390 8G		275 Watts
	Difference: 25 Watts (10%)

Memory Bandwidth

The Radeon R9 390 8G should in theory be much faster than the Radeon HD 4850 X2 512MB overall. (explain)

Radeon R9 390 8G		384000 MB/sec
Radeon HD 4850 X2 512MB		127104 MB/sec
	Difference: 256896 (202%)

Texel Rate

The Radeon R9 390 8G should be quite a bit (more or less 220%) more effective at AF than the Radeon HD 4850 X2 512MB. (explain)

Radeon R9 390 8G		160000 Mtexels/sec
Radeon HD 4850 X2 512MB		50000 Mtexels/sec
	Difference: 110000 (220%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon R9 390 8G is the winner, by far. (explain)

Radeon R9 390 8G		64000 Mpixels/sec
Radeon HD 4850 X2 512MB		20000 Mpixels/sec
	Difference: 44000 (220%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of information (in units of megabytes per second) that can be transferred past the external memory interface in a second. It's worked out by multiplying the interface width by its memory clock speed. If it uses DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This figure is calculated 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 card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly record to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.