Radeon HD 4790 vs Radeon HD 7850

Intro

Compare all that to the Radeon HD 7850, which uses a 28 nm design. AMD has set the core frequency at 860 MHz. The GDDR5 memory runs at a frequency of 1200 MHz on this specific card. It features 1024 SPUs as well as 64 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 7850 should theoretically perform a lot faster than the Radeon HD 4790 overall. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 51200 (50%)

Texel Rate

The Radeon HD 7850 should be quite a bit (about 187%) faster with regards to AF than the Radeon HD 4790. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 35840 (187%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7850 is the winner, by a large margin. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 17920 (187%)

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 largest amount of data (counted in MB per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory speed. In the case of DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This is calculated by multiplying the total texture units 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 in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card can 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 Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.