Radeon HD 3850 256MB vs Radeon HD 4850 X2 1GB

Intro

Compare those specifications to the Radeon HD 4850 X2 1GB, which uses a 55 nm design. AMD has set the core speed at 625 MHz. The GDDR3 memory is set to run at a speed of 993 MHz on this particular model. It features 800(160x5) SPUs along with 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 256MB		75 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 175 Watts (233%)

Memory Bandwidth

The Radeon HD 4850 X2 1GB, in theory, should perform much faster than the Radeon HD 3850 256MB overall. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
Radeon HD 3850 256MB		52992 MB/sec
	Difference: 74112 (140%)

Texel Rate

The Radeon HD 4850 X2 1GB should be much (more or less 368%) faster with regards to texture filtering than the Radeon HD 3850 256MB. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 39312 (368%)

Pixel Rate

The Radeon HD 4850 X2 1GB is a lot (about 87%) better at full screen anti-aliasing than the Radeon HD 3850 256MB, and also should be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
Radeon HD 3850 256MB		10688 Mpixels/sec
	Difference: 9312 (87%)

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: Bandwidth is the max amount of information (in units of MB per second) that can be transferred past the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory speed. In the case of DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the core 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 fill rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.