GeForce GT 640 DDR3 vs Radeon HD 3850 256MB

Intro

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

As far as performance goes, the GeForce GT 640 DDR3 should theoretically be a bit better 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 should be quite a bit (approximately 169%) better at texture filtering 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

If using lots of anti-aliasing is important to you, then the GeForce GT 640 DDR3 is superior to the Radeon HD 3850 256MB, by far. (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: Bandwidth is the max amount of information (in units of megabytes per second) that can be transported across the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory speed. If the card has DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the 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 maximum amount of pixels that the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.