GeForce 9800 GT 512MB vs Radeon HD 4830 512MB

Intro

Compare those specs to the Radeon HD 4830 512MB, which features 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 comprised of 640(128x5) SPUs, 32 Texture Address Units, and 16 Raster Operation Units.

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 memory bandwidth, so in theory they should have identical performance. (explain)

Texel Rate

The GeForce 9800 GT 512MB is much (approximately 83%) faster with regards to anisotropic filtering 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

The GeForce 9800 GT 512MB should be just a bit (approximately 4%) faster with regards to full screen anti-aliasing than the Radeon HD 4830 512MB, and should be able to handle higher screen resolutions better. (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: Bandwidth is the largest amount of information (counted in megabytes per second) that can be transferred across the external memory interface in a second. The number is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed in one second. This is worked out by multiplying the total texture units by the core speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.