Radeon HD 4890 1GB vs Radeon HD 6450 (OEM) 1GB

Intro

Compare those specifications to the Radeon HD 6450 (OEM) 1GB, which uses a 40 nm design. AMD has set the core speed at 750 MHz. The GDDR5 RAM runs at a frequency of 900 MHz on this card. It features 160 SPUs along with 8 Texture Address Units and 4 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6450 (OEM) 1GB		31 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 159 Watts (513%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4890 1GB should in theory be much better than the Radeon HD 6450 (OEM) 1GB in general. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 6450 (OEM) 1GB		28800 MB/sec
	Difference: 96000 (333%)

Texel Rate

The Radeon HD 4890 1GB is a lot (about 567%) faster with regards to AF than the Radeon HD 6450 (OEM) 1GB. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 6450 (OEM) 1GB		6000 Mtexels/sec
	Difference: 34000 (567%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 4890 1GB is a better choice, by far. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
Radeon HD 6450 (OEM) 1GB		3000 Mpixels/sec
	Difference: 13000 (433%)

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 data (counted 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 its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This is worked out by multiplying the total 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 applied in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.