Radeon HD 4790 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 frequency at 1000 MHz. The GDDR5 memory runs at a frequency of 975 MHz on this specific card. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4890 1GB should in theory perform much 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 will be much (more or less 108%) more effective at texture filtering 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 a high screen resolution is important to you, then the Radeon HD 4890 1GB is the winner, and very much so. (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 data (in units of MB per second) that can be transported across the external memory interface in one second. It is worked out by multiplying the interface width by the speed of its memory. In the case of DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. 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 amount of texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

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