Min Htet Paing

im no computer expert but i just stated what previously helped me in a somewhat similar situation. you're welcome though

when it works the second time, try updating the driver (a newer driver might fix the issue)
the same thing happened to me but it was the sound not display and downloading the latest driver fixed it.
 
not sure though...

For gaming, I would suggest you look at monitors from Asus, LG and perhaps brands like Acer, Samsung, etc.  I am not familiar with the last two brands I mentioned but they do make some nice products.  I'm more of a productivity and editing monitor person.

Generally I recommend avoiding the XL2411Z and GN246HL, they are cheap but don't have DisplayPort and don't support 144 Hz over HDMI, which doesn't give much flexibility going forward considering a lot of graphics cards are discontinuing DVI.
 
For cheaper options, the G2460PF or XG2401 are better alternatives. The MG248Q is also pretty good.

Minglabar,
 
For what purpose?  Gaming, office work, design and editing?
 

What is your budget?
A lot of people buy the Asus VG248QE, because it's a pretty good value, but the Acer GN246HL is an even better value

It will just be like a normal monitor.

I got 1440p and idk how I feel about it, I think 1080p was an appropriate size, I just scaled everything up on 1440p. I would go and look at 1440p vs 1080p in a store with monitors or tv's your size, then make a judgement call. 

Honestly, 1440p 144hz is the Gaming sweet spot 

Its personal preference. I take Hz over quality not to mention 4K needs lot more horsepower to drive....

For FPS games  one with 144hz would be best option, for others 1440p. 

Buy a FreeSync monitor, you don't want to spend more on something that you can't use

The monitor will work fine, just Gsync wont work with it without a Nivida GPU, same with freesync monitor. Freesync is cheaper though, which is a good reason to buy AMD. You dont need freesync or gysnc, it can just be nice to have. 

AMD FreeSync monitors are cheaper and you will have variable refresh rates like GSync has on Nvidia GPUs.
 

Well I don't see the point of buying monitor with g-sync if you have AMD GPU.
You will still be able to use monitor, but you won't be able to use g-sync.
 
And I'm pretty sure that whoever spends so much money on monitor, does that because he wants to use g-sync.
So yeah you should save some money and go for freesync monitor if you have AMD card and not planning to go for nvidia anytime soon.

ULMB is only on G-Sync monitors AFAIK. I don't think ASUS's FreeSync monitors have any equivalent.

Save for a little longer and get the Asus MG279Q.  It has every feature you could possibly want in a good monitor and it's only $50 over your budget.  Bonus is that it's FreeSync and you have an AMD GPU.  Here are the highlights: 27" 1440p IPS, 144hz w/FreeSync and 4ms response time, little or no input lag and I believe it also has ULMB if you disable FreeSync (which eliminates motion blur from frame persistence).
 
edit: the reason you want this is that it future proofs you, FreeSync will help with any games where you have frame-rate issues and for competitive games you'll be able to run 120hz + ULMB.  Then when you get a newer GPU (or a new computer) you will already have a 1440p monitor.  Games aren't natively running even 1440p textures, so native 4k games is still *many* years off.

If you already have an RX480 4GB, get a 1080p panel. You won't be playing AAA games at max settings at 1440p with decent frame rates with that GPU. I really like the looks of Dell monitors but I don't think they offer a 1080p monitor with 100+Hz refresh rates (which you want for the best gaming experience you can get with your GPU) and FreeSync (wich you also want) so go with the monitor you like as long as it has the following specs:
1080p
at least 75Hz refresh rate (I would recommend 144Hz, though)
FreeSync (this syncs your refresh rate to your FPS to prevent tearing)
lower than 5-7ms response time
if you can find one: IPS panel (not sure if they are any IPS panels at 1080p 144Hz Freesync) --> this will give you much better colour reproduction and viewing angles than TN (the other common option)

https://www.newegg.com/Product/Product.aspx?Item=N82E16824236722
 
my recommendation, 1080p 144hz is a good sweet spot for the rx 480 (i have the 290x performs similarly to the 480). 1440p is gonna push the card a little too much tbh. 

hmm, thats a hard decision. You should have spent more on the gpu and less on the monitor so you could get a 1070 and a 1440p monitor. Honestly just get a good 1080p monitor. Here is a good one:
 
http://pcpartpicker.com/product/CMCrxr/asus-vg245h-240-75hz-monitor-vg245h