Radeon HD 4650 1GB vs Radeon HD 7850

Intro

Compare that to the Radeon HD 7850, which comes with a core clock speed 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 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 1GB		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 much superior to the Radeon HD 4650 1GB in general. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 131200 (586%)

Texel Rate

The Radeon HD 7850 is a lot (more or less 187%) faster with regards to anisotropic filtering than the Radeon HD 4650 1GB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 35840 (187%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 7850 is a better choice, by far. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4650 1GB		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: Memory bandwidth is the maximum amount of information (measured in MB per second) that can be transferred past the external memory interface in a second. It is worked out by multiplying the bus width by its memory speed. If it uses DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better 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 number of texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at handling 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 record to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units 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 fill rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.