GeForce GT 640 DDR3 vs Radeon HD 3850 1GB

Intro

Compare that to the Radeon HD 3850 1GB, which uses a 55 nm design. AMD has set the core speed at 668 MHz. The GDDR3 memory runs at a speed of 828 MHz on this specific card. It features 320(64x5) SPUs as well as 16 TAUs and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 3850 1GB		75 Watts
	Difference: 10 Watts (15%)

Memory Bandwidth

As far as performance goes, the GeForce GT 640 DDR3 should theoretically be just a bit superior to the Radeon HD 3850 1GB in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
Radeon HD 3850 1GB		52992 MB/sec
	Difference: 4032 (8%)

Texel Rate

The GeForce GT 640 DDR3 should be quite a bit (more or less 169%) better at texture filtering than the Radeon HD 3850 1GB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 3850 1GB		10688 Mtexels/sec
	Difference: 18112 (169%)

Pixel Rate

If using a high screen resolution is important to you, then the GeForce GT 640 DDR3 is the winner, and very much so. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 3850 1GB		10688 Mpixels/sec
	Difference: 3712 (35%)

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 information (counted in megabytes per second) that can be moved across the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster 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 texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.