GeForce GTX 660 Ti vs Radeon HD 4850 X2 1GB

Intro

Compare that to the Radeon HD 4850 X2 1GB, which comes with a clock frequency of 625 MHz and a GDDR3 memory speed of 993 MHz. It also makes use of a 256-bit memory bus, and makes use of a 55 nm design. It is comprised of 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660 Ti		150 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 100 Watts (67%)

Memory Bandwidth

As far as performance goes, the GeForce GTX 660 Ti should in theory be a little bit better than the Radeon HD 4850 X2 1GB overall. (explain)

GeForce GTX 660 Ti		144000 MB/sec
Radeon HD 4850 X2 1GB		127104 MB/sec
	Difference: 16896 (13%)

Texel Rate

The GeForce GTX 660 Ti should be quite a bit (approximately 105%) faster with regards to anisotropic filtering than the Radeon HD 4850 X2 1GB. (explain)

GeForce GTX 660 Ti		102480 Mtexels/sec
Radeon HD 4850 X2 1GB		50000 Mtexels/sec
	Difference: 52480 (105%)

Pixel Rate

The GeForce GTX 660 Ti will be a small bit (more or less 10%) better at full screen anti-aliasing than the Radeon HD 4850 X2 1GB, and also should be capable of handling higher screen resolutions without slowing down too much. (explain)

GeForce GTX 660 Ti		21960 Mpixels/sec
Radeon HD 4850 X2 1GB		20000 Mpixels/sec
	Difference: 1960 (10%)

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 information (measured in MB per second) that can be transferred across the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory speed. In the case of DDR RAM, the result 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 AA, HDR and higher screen 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 number of texture units by the core speed of the chip. The better this number, the better the graphics 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 number of pixels the video card could possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.