Radeon HD 4550 256MB vs Radeon HD 7770

Intro

Compare all of that to the Radeon HD 7770, which features a clock speed of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also makes use of a 128-bit memory bus, and makes use of a 28 nm design. It is comprised of 640 SPUs, 40 TAUs, and 16 Raster Operation Units.

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

The Radeon HD 7770 should theoretically perform quite a bit faster than the Radeon HD 4550 256MB in general. (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 much (approximately 733%) better at anisotropic 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 will be a lot (approximately 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: Bandwidth is the max amount of data (in units of megabytes per second) that can be moved past the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher 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 are processed per second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the 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 number of pixels the video card can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs 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 rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.