GeForce GT 640 DDR3 vs Radeon HD 3850 512MB

Intro

Compare those specs to the Radeon HD 3850 512MB, which features a clock frequency of 668 MHz and a GDDR3 memory frequency of 828 MHz. It also makes use of a 256-bit bus, and uses a 55 nm design. It is made up of 320(64x5) SPUs, 16 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 3850 512MB		75 Watts
	Difference: 10 Watts (15%)

Memory Bandwidth

Theoretically speaking, the GeForce GT 640 DDR3 should be just a bit faster than the Radeon HD 3850 512MB in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
Radeon HD 3850 512MB		52992 MB/sec
	Difference: 4032 (8%)

Texel Rate

The GeForce GT 640 DDR3 is a lot (approximately 169%) more effective at AF than the Radeon HD 3850 512MB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 3850 512MB		10688 Mtexels/sec
	Difference: 18112 (169%)

Pixel Rate

The GeForce GT 640 DDR3 should be a lot (approximately 35%) faster with regards to FSAA than the Radeon HD 3850 512MB, and also will be able to handle higher resolutions more effectively. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 3850 512MB		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 maximum amount of information (in units of megabytes per second) that can be transported past the external memory interface in one second. It's calculated by multiplying the interface width by the speed of its memory. In the case of DDR RAM, it should 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 amount of texture map elements (texels) that can be processed per second. This is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to its 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 clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.