i have a question but not sure if i should ask it here.

im having issues receiving phonecall with my unifi phone. dialing out is not a problem, phone got lotsa static sounds. anyone having this problem? if yes how do u overcome it?

Have you tried a direct cable to confirm its the router?

If the direct cable is problematic as described its likely to be over-heating.  Try placing the router away from the modem .. say 20cm or more.  Also check if the router feels warm to touch or hotter.  I had seen wireless routers randomly disconnect and the cause was traced back to over-heating because other equipment were close by.  Check by turning off wireless when you test with direct cable.

Once you find direct cable is ok and the problem arises for wireless only its likely network congestion.  In my area its like around 10 or more wifi running at any one time.  With 2.4Ghz having 3 effective radio channels and it does not help with some D-Link routers using dual-channel for 802.1n (some vendors for example only use one channel for 2.4Ghz to prevent over-crowding) you will see lots of latency and wifi disconnects.  I run both 5Ghz for my gaming systems and 2.4Ghz on other stuff like PS3 and iPhone.  The 2.4Ghz shows plenty of drops even though the signal is quite strong - prove of network congestion.  And this usually also shows a much much lower speedtest probably because of packets retransmits.  Turning on the "network robustness" option on my router helps a bit at the expense of throughput though.

Then I would suggest you try running on cable for a day or so and wifi off to confirm this.

On your question, actual throughput using dual-channel 5Ghz is around 215Mbps on average.  Reckon it should be much better performance than 2.4Ghz with everything considered.  I get around 200ms to 300ms on MMO gaming to North American servers and don't use any tunneling services.  Most of latency issues are traced back to problems on the 2.4Ghz at least in my case which is why I switched to 5Ghz.  By the way, N-capable devices may not necessarily run on dual-bands so you need to check.  If you go the route of 5Ghz the very nice tutorial to convert the DIR615 as a VLAN switch works like a charm.  Invest in a good router with a solid heatsink and you won't need a cooling pad.  My gear runs 24X7 for years now and don't have any fans or pads on the equipment which are housed inside a cabinet