Radeon HD 3870 1GB vs Radeon HD 4850 2GB

Intro

Compare all of that to the Radeon HD 4850 2GB, which uses a 55 nm design. ATi has set the core frequency at 625 MHz. The GDDR4 memory runs at a frequency of 993 MHz on this model. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 1GB		106 Watts
Radeon HD 4850 2GB		110 Watts
	Difference: 4 Watts (4%)

Memory Bandwidth

The Radeon HD 3870 1GB, in theory, should perform a small bit faster than the Radeon HD 4850 2GB in general. (explain)

Radeon HD 3870 1GB		72000 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 8448 (13%)

Texel Rate

The Radeon HD 4850 2GB will be a lot (about 102%) better at AF than the Radeon HD 3870 1GB. (explain)

Radeon HD 4850 2GB		25000 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 12600 (102%)

Pixel Rate

The Radeon HD 3870 1GB will be much (more or less 24%) better at full screen anti-aliasing than the Radeon HD 4850 2GB, and also capable of handling higher screen resolutions more effectively. (explain)

Radeon HD 3870 1GB		12400 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 2400 (24%)

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 information (measured in MB per second) that can be transferred over the external memory interface within a second. It is calculated by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, 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 are processed per second. This figure is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the 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 most pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel 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 max fill rate.