GeForce 8800 GTS (G80) 640MB vs Radeon HD 3870 X2 512MB

Intro

Compare all that to the Radeon HD 3870 X2 512MB, which features GPU core speed of 825 MHz, and 512 MB of GDDR3 memory set to run at 900 MHz through a 256-bit bus. It also is comprised of 320(64x5) SPUs, 16 Texture Address Units, and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 X2 512MB is 82% faster than the GeForce 8800 GTS (G80) 640MB overall, due to its higher data rate. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 51840 (82%)

Texel Rate

The Radeon HD 3870 X2 512MB should be a little bit (approximately 7%) more effective at anisotropic filtering than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 3870 X2 512MB		26400 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 1776 (7%)

Pixel Rate

The Radeon HD 3870 X2 512MB is a lot (approximately 157%) better at AA than the GeForce 8800 GTS (G80) 640MB, and also will be able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 16140 (157%)

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 (in units of MB per second) that can be moved past the external memory interface in one second. The number is calculated by multiplying the bus width by its memory clock speed. In the case of DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.