Radeon HD 4550 256MB vs Radeon HD 7770

Intro

Compare those specifications to the Radeon HD 7770, which features GPU core speed of 1000 MHz, and 1024 MB of GDDR5 RAM set to run at 1125 MHz through a 128-bit bus. It also is comprised of 640 Stream Processors, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4550 256MB		25 Watts
Radeon HD 7770		80 Watts
	Difference: 55 Watts (220%)

Memory Bandwidth

Theoretically, the Radeon HD 7770 should be quite a bit faster than the Radeon HD 4550 256MB overall. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 4550 256MB		12800 MB/sec
	Difference: 59200 (463%)

Texel Rate

The Radeon HD 7770 will be quite a bit (about 733%) better at texture filtering than the Radeon HD 4550 256MB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 4550 256MB		4800 Mtexels/sec
	Difference: 35200 (733%)

Pixel Rate

The Radeon HD 7770 should be much (more or less 567%) more effective at full screen anti-aliasing than the Radeon HD 4550 256MB, and also will be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 4550 256MB		2400 Mpixels/sec
	Difference: 13600 (567%)

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 (measured in MB per second) that can be transferred across the external memory interface within a second. The number is worked out by multiplying the bus width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better 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 amount of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total 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 processed per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.