GeForce GTX 460 1GB vs Radeon HD 4890 2GB

Intro

Compare all that to the Radeon HD 4890 2GB, which uses a 55 nm design. ATi has clocked the core speed at 1000 MHz. The GDDR5 RAM is set to run at a speed of 975 MHz on this card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 460 1GB		160 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 30 Watts (19%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4890 2GB should in theory be just a bit better than the GeForce GTX 460 1GB overall. (explain)

Radeon HD 4890 2GB		124800 MB/sec
GeForce GTX 460 1GB		115200 MB/sec
	Difference: 9600 (8%)

Texel Rate

The Radeon HD 4890 2GB will be a little bit (more or less 6%) faster with regards to anisotropic filtering than the GeForce GTX 460 1GB. (explain)

Radeon HD 4890 2GB		40000 Mtexels/sec
GeForce GTX 460 1GB		37800 Mtexels/sec
	Difference: 2200 (6%)

Pixel Rate

The GeForce GTX 460 1GB will be quite a bit (about 35%) better at anti-aliasing than the Radeon HD 4890 2GB, and able to handle higher screen resolutions better. (explain)

GeForce GTX 460 1GB		21600 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 5600 (35%)

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 (measured in megabytes per second) that can be transferred over the external memory interface within a second. The number is calculated by multiplying the interface width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total number 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 applied in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.