Radeon HD 3850 256MB vs Radeon HD 4770

Intro

Compare all of that to the Radeon HD 4770, which has clock speeds of 750 MHz on the GPU, and 800 MHz on the 512 MB of GDDR5 memory. It features 640(128x5) SPUs as well as 32 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 256MB		75 Watts
Radeon HD 4770		80 Watts
	Difference: 5 Watts (7%)

Memory Bandwidth

In theory, the Radeon HD 3850 256MB should be 4% faster than the Radeon HD 4770 overall, due to its greater data rate. (explain)

Radeon HD 3850 256MB		52992 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 1792 (4%)

Texel Rate

The Radeon HD 4770 will be a lot (more or less 125%) faster with regards to anisotropic filtering than the Radeon HD 3850 256MB. (explain)

Radeon HD 4770		24000 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 13312 (125%)

Pixel Rate

The Radeon HD 4770 should be a small bit (approximately 12%) faster with regards to FSAA than the Radeon HD 3850 256MB, and will be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 4770		12000 Mpixels/sec
Radeon HD 3850 256MB		10688 Mpixels/sec
	Difference: 1312 (12%)

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 max amount of data (counted in MB per second) that can be moved past the external memory interface in one second. It's worked out by multiplying the bus width by its memory clock speed. If the card has DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the faster 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 amount of texture map elements (texels) that can be applied per second. This is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

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