GeForce GT 640 DDR3 vs Radeon HD 5830

Intro

Compare those specifications to the Radeon HD 5830, which makes use of a 40 nm design. AMD has clocked the core frequency at 800 MHz. The GDDR5 RAM works at a speed of 1000 MHz on this specific card. It features 1120(224x5) SPUs along with 56 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 5830		175 Watts
	Difference: 110 Watts (169%)

Memory Bandwidth

Theoretically, the Radeon HD 5830 should be much faster than the GeForce GT 640 DDR3 in general. (explain)

Radeon HD 5830		128000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 70976 (124%)

Texel Rate

The Radeon HD 5830 will be much (about 56%) faster with regards to AF than the GeForce GT 640 DDR3. (explain)

Radeon HD 5830		44800 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 16000 (56%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the GeForce GT 640 DDR3 is superior to the Radeon HD 5830, but it probably won't make a huge difference. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 5830		12800 Mpixels/sec
	Difference: 1600 (13%)

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 data (in units of megabytes per second) that can be transferred past the external memory interface in one second. It's worked out by multiplying the card's bus width by its memory speed. If it uses DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, 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 can be processed in one second. This number is worked out by multiplying the total number of texture units by the core speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.