Radeon HD 4650 512MB vs Radeon HD 7850

Intro

Compare those specs to the Radeon HD 7850, which comes with a core clock frequency of 860 MHz and a GDDR5 memory frequency of 1200 MHz. It also features a 256-bit bus, and makes use of a 28 nm design. It features 1024 SPUs, 64 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 7850		130 Watts
	Difference: 75 Watts (136%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7850 should theoretically be quite a bit superior to the Radeon HD 4650 512MB overall. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 137600 (860%)

Texel Rate

The Radeon HD 7850 is much (approximately 187%) better at anisotropic filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 35840 (187%)

Pixel Rate

The Radeon HD 7850 should be much (approximately 473%) more effective at anti-aliasing than the Radeon HD 4650 512MB, and also should be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 22720 (473%)

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 (in units of MB per second) that can be transferred over the external memory interface in a second. It is worked out by multiplying the bus width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour 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 output rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.