Radeon HD 4790 vs Radeon HD 4870 X2

Intro

Compare those specifications to the Radeon HD 4870 X2, which makes use of a 55 nm design. AMD has set the core speed at 750 MHz. The GDDR5 memory runs at a frequency of 900 MHz on this specific card. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 4870 X2 is 125% quicker than the Radeon HD 4790 overall, due to its greater data rate. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 128000 (125%)

Texel Rate

The Radeon HD 4870 X2 is quite a bit (approximately 213%) better at anisotropic filtering than the Radeon HD 4790. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 40800 (213%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 4870 X2 is a better choice, by a large margin. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 14400 (150%)

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: Memory bandwidth is the max amount of data (measured in megabytes per second) that can be moved past the external memory interface in one second. It's calculated by multiplying the bus width by the speed of its memory. If it uses DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total amount of texture units by the core clock 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 applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. The figure 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 also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.