Geforce GTX 680 vs Radeon HD 4890 1GB

Intro

Compare all that to the Radeon HD 4890 1GB, which uses a 55 nm design. AMD has set the core speed at 1000 MHz. The GDDR5 RAM runs at a frequency of 975 MHz on this specific model. 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 perform much faster than the Radeon HD 4890 1GB in general. (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 quite a bit (more or less 222%) better at AF 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

The Geforce GTX 680 is a lot (about 101%) better at anti-aliasing than the Radeon HD 4890 1GB, and also able to handle higher resolutions while still performing well. (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: Memory bandwidth is the maximum amount of information (counted in MB per second) that can be transferred over the external memory interface in one second. It's worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better 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 can be processed in one second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

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