GeForce GTS 250 1GB vs Radeon HD 4850 X2 512MB

Intro

Compare that to the Radeon HD 4850 X2 512MB, which comes with GPU clock speed of 625 MHz, and 512 MB of GDDR3 RAM running at 993 MHz through a 256-bit bus. It also features 800(160x5) Stream Processors, 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 GTS 250 1GB		145 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 105 Watts (72%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4850 X2 512MB should be 81% faster than the GeForce GTS 250 1GB overall, due to its higher data rate. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
GeForce GTS 250 1GB		70400 MB/sec
	Difference: 56704 (81%)

Texel Rate

The Radeon HD 4850 X2 512MB is a little bit (more or less 6%) faster with regards to anisotropic filtering than the GeForce GTS 250 1GB. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
GeForce GTS 250 1GB		47232 Mtexels/sec
	Difference: 2768 (6%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 4850 X2 512MB is a better choice, by a large margin. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
GeForce GTS 250 1GB		11808 Mpixels/sec
	Difference: 8192 (69%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the maximum amount of information (measured in megabytes per second) that can be moved past the external memory interface in one second. The number is worked out by multiplying the bus width by the speed of its memory. If the card has DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to the local memory in one 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 - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.