GeForce 9800 GT 512MB vs Radeon HD 3870 512MB

Intro

Compare all that to the Radeon HD 3870 512MB, which comes with a clock frequency of 775 MHz and a GDDR3 memory speed of 900 MHz. It also makes use of a 256-bit memory bus, and uses a 55 nm design. It features 320(64x5) SPUs, 16 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9800 GT 512MB		105 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 1 Watts (1%)

Memory Bandwidth

Both cards have exactly the same bandwidth, so in theory they should perform exactly the same. (explain)

Texel Rate

The GeForce 9800 GT 512MB is quite a bit (about 171%) better at AF than the Radeon HD 3870 512MB. (explain)

GeForce 9800 GT 512MB		33600 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 21200 (171%)

Pixel Rate

The Radeon HD 3870 512MB should be quite a bit (more or less 29%) more effective at anti-aliasing than the GeForce 9800 GT 512MB, and also should be able to handle higher resolutions better. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
GeForce 9800 GT 512MB		9600 Mpixels/sec
	Difference: 2800 (29%)

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 data (in units of MB per second) that can be transported past the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total amount of texture units of the card 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 number of pixels the video card could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.