Radeon HD 4790 vs Radeon R9 280X

Intro

Compare those specs to the Radeon R9 280X, which has GPU clock speed of 850 MHz, and 3072 MB of GDDR5 RAM running at 1500 MHz through a 384-bit bus. It also is made up of 2048 SPUs, 128 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon R9 280X should theoretically be quite a bit superior to the Radeon HD 4790 in general. (explain)

Radeon R9 280X		288000 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 185600 (181%)

Texel Rate

The Radeon R9 280X is much (more or less 467%) faster with regards to texture filtering than the Radeon HD 4790. (explain)

Radeon R9 280X		108800 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 89600 (467%)

Pixel Rate

The Radeon R9 280X is much (approximately 183%) more effective at FSAA than the Radeon HD 4790, and also able to handle higher screen resolutions while still performing well. (explain)

Radeon R9 280X		27200 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 17600 (183%)

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 megabytes per second) that can be transferred past the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This number is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The higher this number, the better the graphics 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 amount of pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units 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, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.