Radeon HD 4770 vs Radeon HD 7850

Intro

Compare those specifications to the Radeon HD 7850, which features a GPU core clock speed of 860 MHz, and 2048 MB of GDDR5 memory running at 1200 MHz through a 256-bit bus. It also is made up of 1024 SPUs, 64 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 7850		130 Watts
	Difference: 50 Watts (63%)

Memory Bandwidth

The Radeon HD 7850 should in theory be much faster than the Radeon HD 4770 in general. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 102400 (200%)

Texel Rate

The Radeon HD 7850 should be a lot (approximately 129%) faster with regards to AF than the Radeon HD 4770. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 31040 (129%)

Pixel Rate

The Radeon HD 7850 should be a lot (more or less 129%) better at AA than the Radeon HD 4770, and will be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 15520 (129%)

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 maximum amount of data (in units of megabytes per second) that can be transported past the external memory interface within a second. It's worked out by multiplying the bus width by its memory clock speed. If it uses DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, 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 texture map elements (texels) that are applied in one second. This figure is calculated by multiplying the total texture units of the card by the core 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 a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour 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 fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.