GeForce 9800 GX2 vs Radeon HD 3870 1GB

Intro

Compare those specifications to the Radeon HD 3870 1GB, which makes use of a 55 nm design. ATi has clocked the core speed at 775 MHz. The GDDR4 memory is set to run at a frequency of 1125 MHz on this card. It features 320(64x5) SPUs as well as 16 Texture Address Units and 16 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 1GB		106 Watts
GeForce 9800 GX2		197 Watts
	Difference: 91 Watts (86%)

Memory Bandwidth

Theoretically speaking, the GeForce 9800 GX2 should perform much faster than the Radeon HD 3870 1GB overall. (explain)

GeForce 9800 GX2		128000 MB/sec
Radeon HD 3870 1GB		72000 MB/sec
	Difference: 56000 (78%)

Texel Rate

The GeForce 9800 GX2 is much (about 519%) faster with regards to AF than the Radeon HD 3870 1GB. (explain)

GeForce 9800 GX2		76800 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 64400 (519%)

Pixel Rate

The GeForce 9800 GX2 is quite a bit (more or less 55%) more effective at full screen anti-aliasing than the Radeon HD 3870 1GB, and also will be able to handle higher screen resolutions without slowing down too much. (explain)

GeForce 9800 GX2		19200 Mpixels/sec
Radeon HD 3870 1GB		12400 Mpixels/sec
	Difference: 6800 (55%)

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 maximum amount of information (measured in megabytes per second) that can be transported over the external memory interface in a second. It is calculated by multiplying the bus width by its memory speed. In the case of DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This number is calculated by multiplying the total amount of texture units of the card by the core 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 per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number 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 outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.