GeForce GTX 280 vs Radeon HD 4850 X2 512MB

Intro

Compare those specs to the Radeon HD 4850 X2 512MB, which uses a 55 nm design. AMD has set the core speed at 625 MHz. The GDDR3 RAM runs at a frequency of 993 MHz on this model. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 280		236 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 14 Watts (6%)

Memory Bandwidth

In theory, the GeForce GTX 280 will be 11% faster than the Radeon HD 4850 X2 512MB in general, because of its higher bandwidth. (explain)

GeForce GTX 280		141696 MB/sec
Radeon HD 4850 X2 512MB		127104 MB/sec
	Difference: 14592 (11%)

Texel Rate

The Radeon HD 4850 X2 512MB will be a bit (about 4%) better at texture filtering than the GeForce GTX 280. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
GeForce GTX 280		48160 Mtexels/sec
	Difference: 1840 (4%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 4850 X2 512MB is a better choice, but only just. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
GeForce GTX 280		19264 Mpixels/sec
	Difference: 736 (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.

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 max amount of information (in units of megabytes per second) that can be transported across the external memory interface within a second. It's calculated by multiplying the card's interface width by its memory speed. In the case of DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. 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 is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.