Geforce GTX 680 vs Radeon HD 4890 1GB

Intro

Compare that to the Radeon HD 4890 1GB, which uses a 55 nm design. AMD has set the core speed at 1000 MHz. The GDDR5 memory works at a frequency of 975 MHz on this particular card. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 1GB		190 Watts
Geforce GTX 680		195 Watts
	Difference: 5 Watts (3%)

Memory Bandwidth

Theoretically speaking, the Geforce GTX 680 should be 54% quicker than the Radeon HD 4890 1GB in general, because of its greater data rate. (explain)

Geforce GTX 680		192256 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 67456 (54%)

Texel Rate

The Geforce GTX 680 will be a lot (about 222%) faster with regards to anisotropic filtering than the Radeon HD 4890 1GB. (explain)

Geforce GTX 680		128768 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 88768 (222%)

Pixel Rate

If using high levels of AA is important to you, then the Geforce GTX 680 is the winner, by far. (explain)

Geforce GTX 680		32192 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 16192 (101%)

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.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the largest amount of data (counted in MB per second) that can be transported over the external memory interface within a second. The number is calculated by multiplying the interface width by the speed of its memory. If the card has DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster 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 in one second. This number is calculated by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.