GeForce GT 640 DDR3 vs GeForce GTS 450

Intro

Compare those specs to the GeForce GTS 450, which has GPU clock speed of 783 MHz, and 512 MB of GDDR5 RAM set to run at 902 MHz through a 128-bit bus. It also features 192 SPUs, 32 Texture Address Units, and 16 ROPs.

Display Graphs

Hide Graphs

Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

GeForce GT 640 DDR3		1560 points
GeForce GTS 450		1453 points
	Difference: 107 (7%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTS 450		106 Watts
	Difference: 41 Watts (63%)

Memory Bandwidth

Theoretically speaking, the GeForce GTS 450 is 1% quicker than the GeForce GT 640 DDR3 overall, because of its higher bandwidth. (explain)

GeForce GTS 450		57728 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 704 (1%)

Texel Rate

The GeForce GT 640 DDR3 will be just a bit (approximately 15%) more effective at anisotropic filtering than the GeForce GTS 450. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce GTS 450		25056 Mtexels/sec
	Difference: 3744 (15%)

Pixel Rate

The GeForce GT 640 DDR3 is a little bit (about 15%) more effective at anti-aliasing than the GeForce GTS 450, and will be able to handle higher screen resolutions without losing too much performance. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce GTS 450		12528 Mpixels/sec
	Difference: 1872 (15%)

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 maximum amount of information (measured in megabytes per second) that can be moved over the external memory interface in a second. It's worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total number of texture units of the card by the core clock 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 one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.