Radeon HD 4670 512MB vs Radeon HD 7990

Intro

Compare those specs to the Radeon HD 7990, which features a clock speed of 950 MHz and a GDDR5 memory speed of 1500 MHz. It also makes use of a 384-bit memory bus, and uses a 28 nm design. It features 2048 SPUs, 128 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4670 512MB		70 Watts
Radeon HD 7990		375 Watts
	Difference: 305 Watts (436%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7990 should be 1700% faster than the Radeon HD 4670 512MB overall, because of its higher bandwidth. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 4670 512MB		32000 MB/sec
	Difference: 544000 (1700%)

Texel Rate

The Radeon HD 7990 should be much (more or less 913%) better at AF than the Radeon HD 4670 512MB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 4670 512MB		24000 Mtexels/sec
	Difference: 219200 (913%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7990 is a better choice, by a large margin. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 4670 512MB		6000 Mpixels/sec
	Difference: 54800 (913%)

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 megabytes per second) that can be moved over the external memory interface in a second. It's worked out by multiplying the bus width by the speed of its memory. If it uses DDR memory, it must be multiplied by 2 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 anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This number is worked out by multiplying the total 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.