Mac OS X has slower internet than other devices in network

[ZaYoOoD]

I just replaced my modem router to a new TP Link (TD-W8968).
Everything worked great, expect for one surprising result.

All the devices (iOS, Windows, Android) in my network get a full download speed of 15 mbps, except for my Macs (Macbook Air & Mac Mini) that get a max of 4 mbps!

Anyone knows what could be the cause?

Also, for some weird reason the upload speed maxed at 0.5 mbps instead of 2 mbps! Even though on the modem setup page it says current down rate is 15 mbps & up rate is 2 mbps..

Any thoughts?

 

[DeltaMac]

Are your speeds slower to the Macs on both wired (ethernet) and wireless?

 

[ZaYoOoD]

Are your speeds slower to the Macs on both wired (ethernet) and wireless?

Yes, I tried connecting my mac directly to the router through an ethernet cable.. Same result!

 

[DeltaMac]

Power-cycle your router while you have ethernet plugged in to your Mac.
Wait for the router to reconnect and settle down, then check again.

What OS X version?

Check your Activity Monitor network tab.

What version of Windows on a PC? Wireless, or wired? Test that PC again, too, after the router reset.
Swap ethernet cables between the PC and your Mac.