GeForce GTX 650 vs Radeon HD 4850 X2 1GB

Intro

Compare those specs to the Radeon HD 4850 X2 1GB, which has a core clock frequency of 625 MHz and a GDDR3 memory speed of 993 MHz. It also uses a 256-bit memory bus, and uses a 55 nm design. It is comprised of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 650		64 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 186 Watts (291%)

Memory Bandwidth

Theoretically, the Radeon HD 4850 X2 1GB should be much faster than the GeForce GTX 650 overall. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
GeForce GTX 650		80000 MB/sec
	Difference: 47104 (59%)

Texel Rate

The Radeon HD 4850 X2 1GB is a lot (approximately 48%) faster with regards to AF than the GeForce GTX 650. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
GeForce GTX 650		33856 Mtexels/sec
	Difference: 16144 (48%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 4850 X2 1GB is a better choice, though only just barely. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
GeForce GTX 650		16928 Mpixels/sec
	Difference: 3072 (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 max amount of information (in units of MB per second) that can be moved across the external memory interface in a second. It's worked out by multiplying the bus width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher 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 can be applied per second. This is calculated by multiplying the total number of texture units by the core 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 per second.

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