Radeon HD 4870 2GB vs Radeon HD 6450 (OEM) 1GB

Intro

Compare that to the Radeon HD 6450 (OEM) 1GB, which comes with GPU clock speed of 750 MHz, and 1024 MB of GDDR5 RAM set to run at 900 MHz through a 64-bit bus. It also is made up of 160 SPUs, 8 TAUs, and 4 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6450 (OEM) 1GB		31 Watts
Radeon HD 4870 2GB		150 Watts
	Difference: 119 Watts (384%)

Memory Bandwidth

The Radeon HD 4870 2GB, in theory, should be a lot faster than the Radeon HD 6450 (OEM) 1GB in general. (explain)

Radeon HD 4870 2GB		115200 MB/sec
Radeon HD 6450 (OEM) 1GB		28800 MB/sec
	Difference: 86400 (300%)

Texel Rate

The Radeon HD 4870 2GB is quite a bit (more or less 400%) faster with regards to texture filtering than the Radeon HD 6450 (OEM) 1GB. (explain)

Radeon HD 4870 2GB		30000 Mtexels/sec
Radeon HD 6450 (OEM) 1GB		6000 Mtexels/sec
	Difference: 24000 (400%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 4870 2GB is the winner, by a large margin. (explain)

Radeon HD 4870 2GB		12000 Mpixels/sec
Radeon HD 6450 (OEM) 1GB		3000 Mpixels/sec
	Difference: 9000 (300%)

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 megabytes per second) that can be transferred over the external memory interface within a second. The number is worked out by multiplying the bus width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the 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 number of texture map elements (texels) that are processed in one second. This figure 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.