Radeon HD 4650 512MB vs Radeon HD 7770

Intro

Compare those specifications to the Radeon HD 7770, which makes use of a 28 nm design. AMD has clocked the core speed at 1000 MHz. The GDDR5 memory runs at a frequency of 1125 MHz on this card. It features 640 SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 7770		80 Watts
	Difference: 25 Watts (45%)

Memory Bandwidth

In theory, the Radeon HD 7770 will be 350% quicker than the Radeon HD 4650 512MB in general, because of its higher bandwidth. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 56000 (350%)

Texel Rate

The Radeon HD 7770 should be quite a bit (approximately 108%) faster with regards to anisotropic filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 20800 (108%)

Pixel Rate

The Radeon HD 7770 should be much (more or less 233%) more effective at AA than the Radeon HD 4650 512MB, and should be able to handle higher resolutions better. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 11200 (233%)

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 information (in units of MB per second) that can be transported across the external memory interface within a second. The number is calculated by multiplying the bus width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

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