GeForce GTX 650 vs Radeon HD 3870 X2 1GB

Intro

Compare that to the Radeon HD 3870 X2 1GB, which uses a 55 nm design. AMD has clocked the core frequency at 825 MHz. The GDDR4 RAM is set to run at a frequency of 1126 MHz on this particular card. It features 320(64x5) SPUs as well as 16 TAUs and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 3870 X2 1GB should be 80% quicker than the GeForce GTX 650 overall, because of its greater data rate. (explain)

Radeon HD 3870 X2 1GB		144128 MB/sec
GeForce GTX 650		80000 MB/sec
	Difference: 64128 (80%)

Texel Rate

The GeForce GTX 650 should be a lot (about 28%) faster with regards to AF than the Radeon HD 3870 X2 1GB. (explain)

GeForce GTX 650		33856 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 7456 (28%)

Pixel Rate

The Radeon HD 3870 X2 1GB is quite a bit (approximately 56%) more effective at anti-aliasing than the GeForce GTX 650, and should be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
GeForce GTX 650		16928 Mpixels/sec
	Difference: 9472 (56%)

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 data (counted in megabytes per second) that can be transferred over the external memory interface in a second. It's calculated by multiplying the interface width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the card will be at 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 could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.