GeForce GTX 660 vs Radeon HD 4890 2GB

Intro

Compare all of that to the Radeon HD 4890 2GB, which comes with a clock frequency of 1000 MHz and a GDDR5 memory speed of 975 MHz. It also makes use of a 256-bit bus, and uses a 55 nm design. It features 800(160x5) SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660		140 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 50 Watts (36%)

Memory Bandwidth

Theoretically speaking, the GeForce GTX 660 should be just a bit faster than the Radeon HD 4890 2GB overall. (explain)

GeForce GTX 660		144192 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 19392 (16%)

Texel Rate

The GeForce GTX 660 will be quite a bit (about 96%) better at texture filtering than the Radeon HD 4890 2GB. (explain)

GeForce GTX 660		78400 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 38400 (96%)

Pixel Rate

If using a high screen resolution is important to you, then the GeForce GTX 660 is superior to the Radeon HD 4890 2GB, and very much so. (explain)

GeForce GTX 660		23520 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 7520 (47%)

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 max amount of data (measured in MB per second) that can be transferred across the external memory interface in a second. It's worked out by multiplying the bus width by its memory clock speed. If it uses DDR RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better 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 number of 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 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 in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.