GeForce GTX 660 vs Radeon HD 4850 X2 1GB

Intro

Compare those specifications to the Radeon HD 4850 X2 1GB, which comes with core clock speeds of 625 MHz on the GPU, and 993 MHz on the 1024 MB of GDDR3 RAM. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

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

Theoretically speaking, the GeForce GTX 660 should perform a small bit faster than the Radeon HD 4850 X2 1GB overall. (explain)

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

Texel Rate

The GeForce GTX 660 should be much (approximately 57%) more effective at anisotropic 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

The GeForce GTX 660 should be a little bit (more or less 18%) better at full screen anti-aliasing than the Radeon HD 4850 X2 1GB, and also capable of handling higher screen resolutions without losing too much performance. (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 largest amount of data (in units of megabytes per second) that can be transported past the external memory interface in one second. It is worked out by multiplying the interface width by its memory clock speed. In the case of DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This is worked out by multiplying the total number of texture units of the card 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 in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The number 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 filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.