Radeon HD 4870 X2 vs Radeon HD 7790

Intro

Compare those specifications to the Radeon HD 7790, which uses a 28 nm design. AMD has set the core frequency at 1000 MHz. The GDDR5 memory is set to run at a speed of 1500 MHz on this specific card. It features 896 SPUs along with 56 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7790		85 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 265 Watts (312%)

Memory Bandwidth

The Radeon HD 4870 X2 should in theory be quite a bit faster than the Radeon HD 7790 in general. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 7790		96000 MB/sec
	Difference: 134400 (140%)

Texel Rate

The Radeon HD 4870 X2 will be a bit (about 7%) more effective at texture filtering than the Radeon HD 7790. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 7790		56000 Mtexels/sec
	Difference: 4000 (7%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 4870 X2 is the winner, by a large margin. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 7790		16000 Mpixels/sec
	Difference: 8000 (50%)

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 (measured in MB per second) that can be transferred across the external memory interface within a second. The number is calculated by multiplying the card's interface width by its memory clock speed. If the card has DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This number is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the video 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 amount of pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number 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 output rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.