Radeon HD 3850 512MB vs Radeon HD 4850 1GB

Intro

Compare those specifications to the Radeon HD 4850 1GB, which uses a 55 nm design. AMD has set the core speed at 625 MHz. The GDDR4 RAM is set to run at a speed of 993 MHz on this particular card. It features 800(160x5) SPUs along with 40 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 512MB		75 Watts
Radeon HD 4850 1GB		110 Watts
	Difference: 35 Watts (47%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4850 1GB is 20% faster than the Radeon HD 3850 512MB in general, due to its greater bandwidth. (explain)

Radeon HD 4850 1GB		63552 MB/sec
Radeon HD 3850 512MB		52992 MB/sec
	Difference: 10560 (20%)

Texel Rate

The Radeon HD 4850 1GB should be a lot (approximately 134%) more effective at anisotropic filtering than the Radeon HD 3850 512MB. (explain)

Radeon HD 4850 1GB		25000 Mtexels/sec
Radeon HD 3850 512MB		10688 Mtexels/sec
	Difference: 14312 (134%)

Pixel Rate

The Radeon HD 3850 512MB will be a bit (approximately 7%) faster with regards to full screen anti-aliasing than the Radeon HD 4850 1GB, and able to handle higher resolutions while still performing well. (explain)

Radeon HD 3850 512MB		10688 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 688 (7%)

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 largest amount of data (in units of megabytes per second) that can be transported past the external memory interface in one second. The number is worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This number is worked out 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units 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 rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.