IF Any defects of Geforce GT 440 1 GB GDDR5?
Wow - what a broad question. By defects I think you mean disadvantages - but that is relative to other cards, and of course their are going to be other cards that are better and faster, and ones that cost more and cost less.
If you want to find the best card for your system, you need to post full system specs - make and model for all major components - and identify the games you play, at what settings and monitor resolutions, and what you budget as.
Alterrnatively, this site has a page to help you identify system requirements relative to upgrading your video card and your preferences:
Or you could go right to looking at reviews for the selected and similar cards:
What games do you play or want to be able to play? What settings?
What is the make and model of your power supply?
The GT 440 is not considered a very good value in a card. See this review:
You can get much better performance for a little more money with the GTS 450, such as this EVGA card for only $100 after rebate and with free shipping:
Note that the review shows the GTS 450 outperforming the GT 440 by 74% on average.
If you don't want to spend that much, you can get an HD 5670 that outperforms the 440 by 10-20% and costs only $60 after rebate - this one the XFX comes with a lifetime warranty:
You could go with a faster video card if budget allows. While it might start to be constrained by other parts of the system, depending on the game, it could still improve FPS by a fair amount for some games.
You still need to confirm that your PSU is large enough for the option you select.
When you can, you should also to increase the amount of memory you have. What operating system are you using and is it 64 or 32 bit?
Geforce GTS 450 released in sep 2010
Geforce GT 440 released in Feb 2011
Is there any relevent?
above two of them have same features like 3D vision,Phyx,pure video Etc...
and DX11,Shader model 5.0,Open GL 4.1,Open CL 1.0 ?
How to calculate a GPU's perfomance?
I knew that a perfomance of grahics card depends upon
1)core clock speed
2)shader clock speed
3)memory clock speed
is the above true?
whats the relevence of a GPU"s Bandwidth Speed and DRam Type?
Dont worry about all the metrics. Those numbers individually are not signficant as performance depends more on how they all work together, with the architecture of the card, with the particular games, game settings, and monitor resolution.
Better approach is to first define your system requirements and personal goals, as explained in more detail here (same site linked above):
That page also explains how to identify your power supply, which you still need to do to confirm what cards will work with your system.
And then look at reviews to compare the perfomance of different cards in the matrix of game, settings, and monitor resolutions fit your plan: