GeForce GT 640 DDR3 vs Radeon HD 4850 2GB

Intro

Compare all of that to the Radeon HD 4850 2GB, which features core speeds of 625 MHz on the GPU, and 993 MHz on the 2048 MB of GDDR4 RAM. It features 800(160x5) SPUs as well as 40 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 4850 2GB		110 Watts
	Difference: 45 Watts (69%)

Memory Bandwidth

The Radeon HD 4850 2GB should theoretically perform a little bit faster than the GeForce GT 640 DDR3 overall. (explain)

Radeon HD 4850 2GB		63552 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 6528 (11%)

Texel Rate

The GeForce GT 640 DDR3 is a small bit (about 15%) faster with regards to AF than the Radeon HD 4850 2GB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 3800 (15%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the GeForce GT 640 DDR3 is a better choice, and very much so. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 4400 (44%)

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 data (in units of megabytes per second) that can be moved over the external memory interface in a second. The number is worked out by multiplying the interface width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, 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 are applied per second. This number is worked out by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill 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 maximum fill rate.