Radeon HD 3850 256MB vs Radeon HD 7770

Intro

Compare all of that to the Radeon HD 7770, which features GPU clock speed of 1000 MHz, and 1024 MB of GDDR5 RAM running at 1125 MHz through a 128-bit bus. It also is made up of 640 Stream Processors, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 256MB		75 Watts
Radeon HD 7770		80 Watts
	Difference: 5 Watts (7%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7770 should perform much faster than the Radeon HD 3850 256MB in general. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 3850 256MB		52992 MB/sec
	Difference: 19008 (36%)

Texel Rate

The Radeon HD 7770 is much (more or less 274%) more effective at anisotropic filtering than the Radeon HD 3850 256MB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 29312 (274%)

Pixel Rate

The Radeon HD 7770 will be quite a bit (more or less 50%) more effective at full screen anti-aliasing than the Radeon HD 3850 256MB, and also will be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 3850 256MB		10688 Mpixels/sec
	Difference: 5312 (50%)

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 megabytes per second) that can be transported over the external memory interface within a second. It is worked out by multiplying the interface width by its memory speed. In the case of DDR type RAM, 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 AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per 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 better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.