Hi Aburik,
The DP to VGA is an active adapter, it is this way due to the nature of converting the signal from digital to analog. 
In regards to your displays, can you detail what displays you have and what are the inputs? 
I can suggest a solution for you.

Hi Paul,
I have 3 Viewsonic V3D231 monitors and one LG monitor (16M65A – only VGA compatible). I am currently having one MiniDP to VGA converter. both these monitors are not DP compatible but both are working with this converter since I have only one converter I checked them by connecting one by one and also I checked this in all MiniDP ports in Graphics card and found it is functioning. My question is can I buy 4 of this MiniDP to VGA converter (It is cheaper in price) to drive all 4 monitors (3- Viewsonic and 1 LG)? Thank you.

Thanks Paul, I intend to use this for 2D purpose. Later I am going to replace these monitors with AOC D2367PH (They are good for stereoscopic 3D, Viewsonic supports stereoscopic 3D only with Tridef (Tridef does not support openGL)). so for my configuration can I use 2 MiniDP to VGA active converters and 2 MiniDP to HDMI passive converter. But as I stated earlier I tried using MiniDP to HDMI passive converter it is not working even for single display. I tried connecting single monitor with this converter and started my system, the window boot up screen appears in the monitor and after starting windows it disappears then only MiniDP to VGA is able to provide display.

If you use two active and two passive it should work. 
Can you check with your adapters vendors if those are actually active? The ones DP to VGA.

My doubt is at least one passive (assuming) MiniDP to HDMI should work right?

Yes, can you just test that adapter on the card to verify if it works?

I tried by connecting single monitor with this converter(MiniDP to HDMI) and starting my operating system, the window boot up screen appears in the monitor and after starting windows it disappears. After this only MiniDP to VGA is able to provide display. I don’t know whether it is because of some Driver issue since it is providing the display till windows boot up.

It could be two issues, a adapter/cable that is defective or the second one which is the driver.
Try using this Display Driver Uninstaller to see if you can reinstall the latest driver and everything works well.
If the latest Omega driver is not working well you can always roll back the driver to 14.9 version. It is available at the amd.com site.

Thanks Paul, I will check and let you know.

You are welcome

Hi Paul, I have attached two pictures with this message. Today I found that miniDP to HDMI passive is working with the graphics card if I don’t install the driver (pic1). Once I install the graphics driver (The one comes with the card or the latest omega driver) it works only up to windows booting. If I connect like pic2 (VGA) it works any time (before and after driver installation). If I connect both always only MiniDP-VGA is working other connectors(monitors) are not getting detected.

Hi,
If you get an image but you dont see it after the driver installation it could be an issue with the display settings in your monitor on the HDMI port. Can you tell me the make and model of those adapters?

It is not about image, After installing It is not detecting the monitor at all. I Checked this by connecting both VGA and HDMI but it detects only VGA monitor not the HDMI monitor. If I connect only HDMI it is not detecting. In monitor I am getting no signal indication. If I connect VGA then no problem it detects and working. Adapter cable  does not contain any name on it. It is purchased locally.

I can buy the active HDMI adapter but my worry is whether it will detect and work along with VGA adapter?

Thanks.

It has to work along with the VGA adapter. We have tested here internally your setup (except we use Club 3D branded adapters) and works fine in both Omega and 14.9 drivers.

Good morning Paul. Club3D adapters are not available in my country (India). This graphics cards I imported from Germany. Can you please suggest some other cable. If you can please post the connected picture like how I had posted earlier (It will help me to see the configuration).
Thank you.

Hi,
I am sorry I cannot help you there as I do not know which vendors sells in your local market. 
I suggest to check on other local forums to verify which are the best options for you.
Regards

Let me try to find the solution. Thank you, very much Paul. You helped a lot.

You can use two active and two passive adapters. It also all depends on the resolution you are using. Lets say that you have displays that go above 1200p, then you will need active adapters.
Viewsonic V3D231 both are 1080p (you can use two passive miniDP to HDMI™)
acer AL1716 d-sub.DVI (here you can use active adapters)
LG 16M65A I cannot find information but you can use here active adapters just in case.

Thanks Paul. My requirement is to use 3 HDMI monitors (Viewsonic V3D231) and one VGA. I have no problem connecting 2 Viewsonic monitor with active HDMI and one LG with VGA but 3rd HDMI Viewsonic monitor is not working with VGA (passive miniDP to HDMI is not working). I want to know can I connect 3 miniDP to active HDMI and one miniDP to VGA in this card?

Hi,
Like I have explained, if you are using two passive and two active it should work, not sure why is not working in your case.
If you use an active adapter it should definitely work.

Thanks Paul. I will buy one more miniDP to Active HDMI cable. I will update the result after testing.

Thank you. Let me know if you have any other question.