Radeon HD 3650 vs Radeon HD 6990

Intro

Compare all that to the Radeon HD 6990, which comes with GPU core speed of 830 MHz, and 2048 MB of GDDR5 memory running at 1250 MHz through a 256-bit bus. It also is made up of 1536 SPUs, 96 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3650		78 Watts
Radeon HD 6990		375 Watts
	Difference: 297 Watts (381%)

Memory Bandwidth

The Radeon HD 6990 should in theory be quite a bit faster than the Radeon HD 3650 in general. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 3650		25600 MB/sec
	Difference: 294400 (1150%)

Texel Rate

The Radeon HD 6990 is quite a bit (approximately 2648%) more effective at anisotropic filtering than the Radeon HD 3650. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 3650		5800 Mtexels/sec
	Difference: 153560 (2648%)

Pixel Rate

The Radeon HD 6990 should be much (about 1732%) faster with regards to FSAA than the Radeon HD 3650, and also will be capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 3650		2900 Mpixels/sec
	Difference: 50220 (1732%)

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: Memory bandwidth is the max amount of data (counted in megabytes per second) that can be moved across the external memory interface within a second. It's calculated by multiplying the bus width by the speed of its memory. If it uses DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

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