GeForce 9800 GTX vs Radeon HD 4850 2GB

Intro

Compare those specs to the Radeon HD 4850 2GB, which comes with a clock frequency of 625 MHz and a GDDR4 memory speed of 993 MHz. It also uses a 256-bit memory bus, and uses a 55 nm design. It is made up 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)

Radeon HD 4850 2GB		110 Watts
GeForce 9800 GTX		140 Watts
	Difference: 30 Watts (27%)

Memory Bandwidth

As far as performance goes, the GeForce 9800 GTX should in theory be just a bit superior to the Radeon HD 4850 2GB overall. (explain)

GeForce 9800 GTX		70400 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 6848 (11%)

Texel Rate

The GeForce 9800 GTX should be much (more or less 73%) more effective at AF than the Radeon HD 4850 2GB. (explain)

GeForce 9800 GTX		43200 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 18200 (73%)

Pixel Rate

The GeForce 9800 GTX will be just a bit (about 8%) faster with regards to anti-aliasing than the Radeon HD 4850 2GB, and also will be able to handle higher screen resolutions more effectively. (explain)

GeForce 9800 GTX		10800 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 800 (8%)

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 information (in units of MB per second) that can be transferred across the external memory interface in a second. It's worked out by multiplying the bus width by its memory speed. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at handling 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 can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs 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 bandwidth is, the lower the ability to get to the max fill rate.