GeForce GTX 275 vs Radeon HD 4790

Intro

Compare those specifications to the Radeon HD 4790, which uses a 55 nm design. AMD has set the core frequency at 600 MHz. The GDDR5 RAM works at a frequency of 800 MHz on this particular card. It features 640(128x5) SPUs as well as 32 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the GeForce GTX 275 is 24% quicker than the Radeon HD 4790 overall, because of its higher data rate. (explain)

GeForce GTX 275		127008 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 24608 (24%)

Texel Rate

The GeForce GTX 275 will be much (approximately 164%) more effective at anisotropic filtering than the Radeon HD 4790. (explain)

GeForce GTX 275		50640 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 31440 (164%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the GeForce GTX 275 is superior to the Radeon HD 4790, by a large margin. (explain)

GeForce GTX 275		17724 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 8124 (85%)

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.

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 within a second. The number is worked out by multiplying the 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 card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the 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 most pixels the video card can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core 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 rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.