Radeon HD 6450 (OEM) 1GB vs Radeon HD 6990

Intro

Compare all that to the Radeon HD 6990, which features clock speeds of 830 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 RAM. It features 1536 SPUs along with 96 Texture Address Units and 32 Rasterization Operator 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 6990		375 Watts
	Difference: 344 Watts (1110%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6990 is 1011% quicker than the Radeon HD 6450 (OEM) 1GB in general, because of its higher data rate. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 6450 (OEM) 1GB		28800 MB/sec
	Difference: 291200 (1011%)

Texel Rate

The Radeon HD 6990 is quite a bit (about 2556%) more effective at anisotropic filtering than the Radeon HD 6450 (OEM) 1GB. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 6450 (OEM) 1GB		6000 Mtexels/sec
	Difference: 153360 (2556%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 6990 is a better choice, by a large margin. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 6450 (OEM) 1GB		3000 Mpixels/sec
	Difference: 50120 (1671%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of data (in units of megabytes per second) that can be transferred over the external memory interface in a second. It's calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, 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 amount of texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.