GeForce GTX 275 vs Radeon HD 7990

Intro

Compare that to the Radeon HD 7990, which features a clock frequency of 950 MHz and a GDDR5 memory frequency of 1500 MHz. It also makes use of a 384-bit bus, and makes use of a 28 nm design. It is comprised 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)

GeForce GTX 275		219 Watts
Radeon HD 7990		375 Watts
	Difference: 156 Watts (71%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7990 should in theory be much superior to the GeForce GTX 275 in general. (explain)

Radeon HD 7990		576000 MB/sec
GeForce GTX 275		127008 MB/sec
	Difference: 448992 (354%)

Texel Rate

The Radeon HD 7990 should be a lot (approximately 380%) better at AF than the GeForce GTX 275. (explain)

Radeon HD 7990		243200 Mtexels/sec
GeForce GTX 275		50640 Mtexels/sec
	Difference: 192560 (380%)

Pixel Rate

The Radeon HD 7990 should be quite a bit (about 243%) better at anti-aliasing than the GeForce GTX 275, and able to handle higher resolutions more effectively. (explain)

Radeon HD 7990		60800 Mpixels/sec
GeForce GTX 275		17724 Mpixels/sec
	Difference: 43076 (243%)

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 maximum amount of data (in units of megabytes per second) that can be transported across the external memory interface within a second. The number is worked out by multiplying the bus width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.