Radeon HD 4670 1GB vs Radeon HD 7990

Intro

Compare all of that to the Radeon HD 7990, which has 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 makes use of a 28 nm design. It is made up of 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 1GB		70 Watts
Radeon HD 7990		375 Watts
	Difference: 305 Watts (436%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7990 is 1536% quicker than the Radeon HD 4670 1GB in general, due to its higher data rate. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 4670 1GB		35200 MB/sec
	Difference: 540800 (1536%)

Texel Rate

The Radeon HD 7990 will be quite a bit (approximately 913%) more effective at texture filtering than the Radeon HD 4670 1GB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 4670 1GB		24000 Mtexels/sec
	Difference: 219200 (913%)

Pixel Rate

The Radeon HD 7990 should be quite a bit (about 913%) more effective at full screen anti-aliasing than the Radeon HD 4670 1GB, and able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 4670 1GB		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 largest amount of data (measured in MB per second) that can be moved over the external memory interface in one second. It is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster 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 figure is calculated by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.