GeForce 9800 GT 512MB vs Radeon HD 4830 512MB

Intro

Compare that to the Radeon HD 4830 512MB, which has a clock speed of 575 MHz and a GDDR3 memory frequency of 900 MHz. It also features a 256-bit bus, and makes use of a 55 nm design. It is made up of 640(128x5) SPUs, 32 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
GeForce 9800 GT 512MB		105 Watts
	Difference: 10 Watts (11%)

Memory Bandwidth

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

Texel Rate

The GeForce 9800 GT 512MB is quite a bit (about 83%) more effective at AF than the Radeon HD 4830 512MB. (explain)

GeForce 9800 GT 512MB		33600 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 15200 (83%)

Pixel Rate

If running with high levels of AA is important to you, then the GeForce 9800 GT 512MB is the winner, but not by far. (explain)

GeForce 9800 GT 512MB		9600 Mpixels/sec
Radeon HD 4830 512MB		9200 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: Memory bandwidth is the max amount of data (measured in MB per second) that can be transferred over the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. 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 texture map elements (texels) that can be applied in one second. This is worked out by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the most 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 number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.