Radeon HD 3850 X2 vs Radeon HD 4890 1GB

Intro

Compare that to the Radeon HD 4890 1GB, which features a clock frequency of 1000 MHz and a GDDR5 memory speed of 975 MHz. It also features a 256-bit bus, and uses a 55 nm design. It is made up of 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4890 1GB, in theory, should be a bit faster than the Radeon HD 3850 X2 overall. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 3850 X2		105984 MB/sec
	Difference: 18816 (18%)

Texel Rate

The Radeon HD 4890 1GB will be quite a bit (approximately 87%) faster with regards to AF than the Radeon HD 3850 X2. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 18624 (87%)

Pixel Rate

The Radeon HD 3850 X2 will be a lot (approximately 34%) more effective at FSAA than the Radeon HD 4890 1GB, and will be capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 3850 X2		21376 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 5376 (34%)

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 largest amount of information (measured in megabytes per second) that can be transported across the external memory interface within a second. The number is calculated by multiplying the interface width by its memory speed. If the card has DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the 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 processed in one second. This figure is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the video 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 maximum number of pixels that the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.