GeForce GTX 660 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 runs at a speed of 800 MHz on this specific model. It features 640(128x5) SPUs along with 32 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The GeForce GTX 660 should in theory perform quite a bit faster than the Radeon HD 4790 in general. (explain)

GeForce GTX 660		144192 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 41792 (41%)

Texel Rate

The GeForce GTX 660 will be a lot (approximately 308%) more effective at texture filtering than the Radeon HD 4790. (explain)

GeForce GTX 660		78400 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 59200 (308%)

Pixel Rate

If running with high levels of AA is important to you, then the GeForce GTX 660 is a better choice, by far. (explain)

GeForce GTX 660		23520 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 13920 (145%)

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: Memory bandwidth is the maximum amount of data (in units of megabytes per second) that can be transferred over the external memory interface in a second. It's calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the 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 texture map elements (texels) that are processed per second. This number is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics 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 amount of pixels that the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines 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 lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.