Radeon HD 3850 512MB vs Radeon HD 4850 1GB

Intro

Compare all of that to the Radeon HD 4850 1GB, which makes use of a 55 nm design. ATi has clocked the core frequency at 625 MHz. The GDDR4 memory runs at a speed of 993 MHz on this specific model. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

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

In theory, the Radeon HD 4850 1GB will be 20% quicker 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 will be much (approximately 134%) more effective at AF 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 is a bit (about 7%) faster with regards to AA than the Radeon HD 4850 1GB, and should be able to handle higher resolutions more effectively. (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 max amount of data (counted in megabytes per second) that can be transported across the external memory interface in a second. The number is calculated by multiplying the card's bus width by its memory speed. If the card has DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics 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 most pixels that the graphics chip can possibly write to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.