GeForce GTX 660 vs Radeon HD 4850 X2 1GB

Intro

Compare all that to the Radeon HD 4850 X2 1GB, which uses a 55 nm design. AMD has clocked the core speed at 625 MHz. The GDDR3 memory works at a speed of 993 MHz on this model. It features 800(160x5) SPUs along with 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660		140 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 110 Watts (79%)

Memory Bandwidth

Performance-wise, the GeForce GTX 660 should theoretically be a small bit better than the Radeon HD 4850 X2 1GB in general. (explain)

GeForce GTX 660		144192 MB/sec
Radeon HD 4850 X2 1GB		127104 MB/sec
	Difference: 17088 (13%)

Texel Rate

The GeForce GTX 660 will be much (more or less 57%) better at texture filtering than the Radeon HD 4850 X2 1GB. (explain)

GeForce GTX 660		78400 Mtexels/sec
Radeon HD 4850 X2 1GB		50000 Mtexels/sec
	Difference: 28400 (57%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the GeForce GTX 660 is superior to the Radeon HD 4850 X2 1GB, though only just barely. (explain)

GeForce GTX 660		23520 Mpixels/sec
Radeon HD 4850 X2 1GB		20000 Mpixels/sec
	Difference: 3520 (18%)

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 moved across the external memory interface in one second. It's calculated by multiplying the interface width by its memory clock speed. If the card has DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better 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 amount of texture map elements (texels) that are applied in one second. This number is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.