Radeon HD 4750 vs Radeon HD 4850 512MB

Intro

Compare those specifications to the Radeon HD 4850 512MB, which has a clock speed of 625 MHz and a GDDR3 memory frequency of 993 MHz. It also features a 256-bit memory bus, and uses a 55 nm design. It features 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4750		75 Watts
Radeon HD 4850 512MB		110 Watts
	Difference: 35 Watts (47%)

Memory Bandwidth

In theory, the Radeon HD 4850 512MB should be a lot faster than the Radeon HD 4750 in general. (explain)

Radeon HD 4850 512MB		63552 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 12352 (24%)

Texel Rate

The Radeon HD 4850 512MB should be just a bit (about 7%) faster with regards to AF than the Radeon HD 4750. (explain)

Radeon HD 4850 512MB		25000 Mtexels/sec
Radeon HD 4750		23360 Mtexels/sec
	Difference: 1640 (7%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 4750 is a better choice, but it probably won't make a huge difference. (explain)

Radeon HD 4750		11680 Mpixels/sec
Radeon HD 4850 512MB		10000 Mpixels/sec
	Difference: 1680 (17%)

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 past the external memory interface in one second. It is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, 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 maximum number of pixels the video card could possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.