GeForce GT 640 DDR3 vs Radeon HD 4830 512MB

Intro

Compare all that to the Radeon HD 4830 512MB, which comes with core speeds of 575 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 memory. It features 640(128x5) SPUs along with 32 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 4830 512MB		95 Watts
	Difference: 30 Watts (46%)

Memory Bandwidth

The Radeon HD 4830 512MB should in theory be a bit faster than the GeForce GT 640 DDR3 overall. (explain)

Radeon HD 4830 512MB		57600 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 576 (1%)

Texel Rate

The GeForce GT 640 DDR3 will be quite a bit (more or less 57%) better at AF than the Radeon HD 4830 512MB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 10400 (57%)

Pixel Rate

If running with a high screen resolution is important to you, then the GeForce GT 640 DDR3 is superior to the Radeon HD 4830 512MB, by far. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 4830 512MB		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 max amount of data (in units of megabytes per second) that can be transferred over the external memory interface in one second. It is calculated by multiplying the interface width by its memory speed. In the case of DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to the 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 core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.