GeForce GT 640 DDR3 vs Radeon HD 5830

Intro

Compare those specs to the Radeon HD 5830, which uses a 40 nm design. AMD has set the core frequency at 800 MHz. The GDDR5 RAM is set to run at a speed of 1000 MHz on this model. It features 1120(224x5) SPUs as well as 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

Performance-wise, the Radeon HD 5830 should in theory be a lot superior to the GeForce GT 640 DDR3 overall. (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 a lot (approximately 56%) more effective at texture filtering 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

The GeForce GT 640 DDR3 is just a bit (about 13%) more effective at AA than the Radeon HD 5830, and also should be able to handle higher resolutions while still performing well. (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 over the external memory interface in a second. It is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster 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 figure is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the 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 most pixels that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.