GeForce GT 640 DDR3 vs Radeon HD 3850 256MB

Intro

Compare all that to the Radeon HD 3850 256MB, which has clock speeds of 668 MHz on the GPU, and 828 MHz on the 256 MB of GDDR3 memory. It features 320(64x5) SPUs as well as 16 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 3850 256MB		75 Watts
	Difference: 10 Watts (15%)

Memory Bandwidth

In theory, the GeForce GT 640 DDR3 should be just a bit faster than the Radeon HD 3850 256MB in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
Radeon HD 3850 256MB		52992 MB/sec
	Difference: 4032 (8%)

Texel Rate

The GeForce GT 640 DDR3 is a lot (more or less 169%) faster with regards to AF than the Radeon HD 3850 256MB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 18112 (169%)

Pixel Rate

The GeForce GT 640 DDR3 should be quite a bit (approximately 35%) more effective at FSAA than the Radeon HD 3850 256MB, and also should be able to handle higher screen resolutions without slowing down too much. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 3850 256MB		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 largest amount of data (measured in MB per second) that can be transferred past the external memory interface in one second. It is calculated by multiplying the bus width by its memory speed. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one 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 worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.