Radeon HD 4650 512MB vs Radeon HD 7970

Intro

Compare those specifications to the Radeon HD 7970, which uses a 28 nm design. AMD has clocked the core speed at 925 MHz. The GDDR5 RAM is set to run at a speed of 1375 MHz on this specific card. It features 2048 SPUs along with 128 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 7970		250 Watts
	Difference: 195 Watts (355%)

Memory Bandwidth

In theory, the Radeon HD 7970 will be 1550% quicker than the Radeon HD 4650 512MB in general, due to its higher bandwidth. (explain)

Radeon HD 7970		264000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 248000 (1550%)

Texel Rate

The Radeon HD 7970 should be a lot (approximately 517%) faster with regards to texture filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 7970		118400 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 99200 (517%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 7970 is superior to the Radeon HD 4650 512MB, by far. (explain)

Radeon HD 7970		29600 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 24800 (517%)

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 maximum amount of information (measured in MB per second) that can be moved over the external memory interface in a second. It is calculated by multiplying the card's bus width by its memory speed. In the case of DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster 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 figure is worked out by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.