Radeon HD 3850 X2 vs Radeon HD 4890 2GB

Intro

Compare those specs to the Radeon HD 4890 2GB, which has a clock frequency of 1000 MHz and a GDDR5 memory speed of 975 MHz. It also makes use of a 256-bit memory bus, and uses a 55 nm design. It is comprised of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 4890 2GB should be 18% faster than the Radeon HD 3850 X2 overall, because of its higher bandwidth. (explain)

Radeon HD 4890 2GB		124800 MB/sec
Radeon HD 3850 X2		105984 MB/sec
	Difference: 18816 (18%)

Texel Rate

The Radeon HD 4890 2GB will be a lot (about 87%) better at anisotropic filtering than the Radeon HD 3850 X2. (explain)

Radeon HD 4890 2GB		40000 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 18624 (87%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 3850 X2 is a better choice, by a large margin. (explain)

Radeon HD 3850 X2		21376 Mpixels/sec
Radeon HD 4890 2GB		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: Bandwidth is the maximum amount of data (in units of MB per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, 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 anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.