Radeon HD 3870 X2 1GB vs Radeon HD 4850 2GB

Intro

Compare those specs to the Radeon HD 4850 2GB, which makes use of a 55 nm design. AMD has clocked the core frequency at 625 MHz. The GDDR4 memory runs at a frequency of 993 MHz on this specific card. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 3870 X2 1GB should perform quite a bit faster than the Radeon HD 4850 2GB in general. (explain)

Radeon HD 3870 X2 1GB		144128 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 80576 (127%)

Texel Rate

The Radeon HD 3870 X2 1GB is a little bit (about 6%) more effective at texture filtering than the Radeon HD 4850 2GB. (explain)

Radeon HD 3870 X2 1GB		26400 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 1400 (6%)

Pixel Rate

The Radeon HD 3870 X2 1GB will be quite a bit (about 164%) more effective at FSAA than the Radeon HD 4850 2GB, and also capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 16400 (164%)

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 (counted in MB per second) that can be transported across the external memory interface in one second. It's worked out by multiplying the bus width by its memory speed. In the case of DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster 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 applied in one second. This figure is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to 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 memory bandwidth is, the lower the ability to get to the maximum fill rate.