Radeon HD 4750 vs Radeon HD 4850 512MB

Intro

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

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

Theoretically, the Radeon HD 4850 512MB should be much faster than the Radeon HD 4750 overall. (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 a bit (approximately 7%) faster with regards to anisotropic filtering than the Radeon HD 4750. (explain)

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

Pixel Rate

The Radeon HD 4750 should be a little bit (about 17%) more effective at anti-aliasing than the Radeon HD 4850 512MB, and also will be able to handle higher resolutions without slowing down too much. (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: Memory bandwidth is the maximum amount of information (measured in MB per second) that can be transferred past the external memory interface in a second. It is worked out by multiplying the bus width by the speed of its memory. If the card has DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.