GeForce 9800 GT 512MB vs Radeon HD 4850 2GB

Intro

Compare those specifications to the Radeon HD 4850 2GB, which features GPU clock speed of 625 MHz, and 2048 MB of GDDR4 RAM running at 993 MHz through a 256-bit bus. It also is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9800 GT 512MB		105 Watts
Radeon HD 4850 2GB		110 Watts
	Difference: 5 Watts (5%)

Memory Bandwidth

In theory, the Radeon HD 4850 2GB is 10% quicker than the GeForce 9800 GT 512MB in general, due to its higher bandwidth. (explain)

Radeon HD 4850 2GB		63552 MB/sec
GeForce 9800 GT 512MB		57600 MB/sec
	Difference: 5952 (10%)

Texel Rate

The GeForce 9800 GT 512MB should be much (approximately 34%) more effective at texture filtering than the Radeon HD 4850 2GB. (explain)

GeForce 9800 GT 512MB		33600 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 8600 (34%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 4850 2GB is the winner, but it probably won't make a huge difference. (explain)

Radeon HD 4850 2GB		10000 Mpixels/sec
GeForce 9800 GT 512MB		9600 Mpixels/sec
	Difference: 400 (4%)

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: Bandwidth is the maximum amount of data (measured in megabytes per second) that can be transported past the external memory interface within a second. It's calculated by multiplying the bus width by the speed of its memory. In the case of DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the 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 amount of texture units by the core clock speed of the chip. The higher this number, 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 maximum amount of pixels that the graphics chip could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.