GeForce GT 640 DDR3 vs Radeon HD 5870

Intro

Compare those specifications to the Radeon HD 5870, which makes use of a 40 nm design. AMD has set the core frequency at 850 MHz. The GDDR5 memory works at a speed of 1200 MHz on this particular card. It features 1600(320x5) SPUs as well as 80 TAUs and 32 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 5870		188 Watts
	Difference: 123 Watts (189%)

Memory Bandwidth

The Radeon HD 5870 should in theory perform quite a bit faster than the GeForce GT 640 DDR3 overall. (explain)

Radeon HD 5870		153600 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 96576 (169%)

Texel Rate

The Radeon HD 5870 should be a lot (more or less 136%) faster with regards to AF than the GeForce GT 640 DDR3. (explain)

Radeon HD 5870		68000 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 39200 (136%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 5870 is a better choice, by far. (explain)

Radeon HD 5870		27200 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 12800 (89%)

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 max amount of data (in units of megabytes per second) that can be moved across the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory speed. If the card has DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, 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 texture map elements (texels) that are applied in one second. This number is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to its local memory in a 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 - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.