Radeon HD 4790 vs Radeon HD 4890 1GB

Intro

Compare those specs to the Radeon HD 4890 1GB, which makes use of a 55 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 memory runs at a speed of 975 MHz on this model. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4890 1GB, in theory, should perform a lot faster than the Radeon HD 4790 overall. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 22400 (22%)

Texel Rate

The Radeon HD 4890 1GB is quite a bit (approximately 108%) faster with regards to AF than the Radeon HD 4790. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 20800 (108%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 4890 1GB is the winner, by far. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 6400 (67%)

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 information (measured in MB per second) that can be transferred across the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher 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 are applied in one second. This figure is worked out by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the video 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 amount of pixels the video card could possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.