GeForce 9800 GT 512MB vs Radeon HD 7990

Intro

Compare all that to the Radeon HD 7990, which features a core clock speed of 950 MHz and a GDDR5 memory speed of 1500 MHz. It also features a 384-bit memory bus, and makes use of a 28 nm design. It is comprised of 2048 SPUs, 128 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9800 GT 512MB		105 Watts
Radeon HD 7990		375 Watts
	Difference: 270 Watts (257%)

Memory Bandwidth

In theory, the Radeon HD 7990 is 900% faster than the GeForce 9800 GT 512MB in general, because of its greater data rate. (explain)

Radeon HD 7990		576000 MB/sec
GeForce 9800 GT 512MB		57600 MB/sec
	Difference: 518400 (900%)

Texel Rate

The Radeon HD 7990 should be much (about 624%) better at anisotropic filtering than the GeForce 9800 GT 512MB. (explain)

Radeon HD 7990		243200 Mtexels/sec
GeForce 9800 GT 512MB		33600 Mtexels/sec
	Difference: 209600 (624%)

Pixel Rate

The Radeon HD 7990 is quite a bit (approximately 533%) more effective at anti-aliasing than the GeForce 9800 GT 512MB, and also able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 7990		60800 Mpixels/sec
GeForce 9800 GT 512MB		9600 Mpixels/sec
	Difference: 51200 (533%)

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 information (in units of MB per second) that can be moved across the external memory interface in a second. It is calculated by multiplying the card's bus width by its memory speed. In the case of DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, 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 processed in one second. This 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 video 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 the graphics card can possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.