GeForce GT 640 DDR3 vs Radeon HD 4830 1GB

Intro

Compare those specs to the Radeon HD 4830 1GB, which features GPU clock speed of 575 MHz, and 1024 MB of GDDR4 RAM running at 900 MHz through a 256-bit bus. It also is made up of 640(128x5) SPUs, 32 TAUs, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 4830 1GB		95 Watts
	Difference: 30 Watts (46%)

Memory Bandwidth

The Radeon HD 4830 1GB, in theory, should perform a small bit faster than the GeForce GT 640 DDR3 overall. (explain)

Radeon HD 4830 1GB		57600 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 576 (1%)

Texel Rate

The GeForce GT 640 DDR3 is a lot (more or less 57%) better at AF than the Radeon HD 4830 1GB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 10400 (57%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the GeForce GT 640 DDR3 is the winner, by far. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 5200 (57%)

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 maximum amount of information (measured in megabytes per second) that can be moved over the external memory interface in one second. It is worked out by multiplying the card's interface width by its memory speed. In the case of DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better 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 number of texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour 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, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.