Radeon HD 4650 512MB vs Radeon HD 5550

Intro

Compare all that to the Radeon HD 5550, which has clock speeds of 550 MHz on the GPU, and 400 MHz on the 512 MB of DDR2 RAM. It features 320(64x5) SPUs as well as 16 Texture Address Units and 8 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4650 512MB, in theory, should perform much faster than the Radeon HD 5550 overall. (explain)

Radeon HD 4650 512MB		16000 MB/sec
Radeon HD 5550		12800 MB/sec
	Difference: 3200 (25%)

Texel Rate

The Radeon HD 4650 512MB will be quite a bit (about 118%) faster with regards to AF than the Radeon HD 5550. (explain)

Radeon HD 4650 512MB		19200 Mtexels/sec
Radeon HD 5550		8800 Mtexels/sec
	Difference: 10400 (118%)

Pixel Rate

The Radeon HD 4650 512MB will be a little bit (more or less 9%) faster with regards to FSAA than the Radeon HD 5550, and also should be able to handle higher resolutions while still performing well. (explain)

Radeon HD 4650 512MB		4800 Mpixels/sec
Radeon HD 5550		4400 Mpixels/sec
	Difference: 400 (9%)

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 (in units of megabytes per second) that can be transferred across the external memory interface within a second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the 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 texture map elements (texels) that can be applied per second. This is worked out by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.