@Crazy4wifi 

If you are running the speed test from the router, you may not have control of what server it connects to for the test.  Ideally, it tries to connect to a server with the lowest latency, but it has been my experience that this is not always the case.  Try running the test from a speed test website, from a wired device, to see what speeds you get.  Pay attention to what server the service chooses

I would first try swapping your LN cable from the modem to your router.  Old or cheap cables can be "noisey" slowing your effective data rates.  Make sure you have at least a DOCSIS 3.0 modem.  ISPs are notorious for upselling existing customer without providing new equipment that can take advantage of those speeds.  In your case, this is highly unlikely as older modems were only capable of 40 MBts down.   

WiFi speeds will never be as fast as the advertised speeds from ISP.  To get best speeds, you need to be connected to the 5GHz band and be close to the router.  The further away you are, or the more crowded your area is with WiFi networks, the slower you can expect your connection to be.  Apartment complexes tend to be difficult to get  good speeds due to a lot of interference from other networks.  Also, your speeds will also rely on the capabilities of the device connected.  Make sure drivers from computers are up to date and mobile devices have the latest updates from carrier installed.  Older hardware may be a bottleneck.

If you have an android device, you can install a WiFi analyzer app to see what channels are being used around you and you can try to manually configure a less congested channel in the routers web GUI.  Apple devices lock down the WiFi chipset from being used for this purpose.  inSSIDer can be installed on PCs to analyze channel usage in your area as well. 

Honestly, 525 is not bad for a wireless connection if that is where your speed was measured.  My son can only get decent speeds if he is in the same room as the router.  From the other side of his apartment, his speeds are 50 MBs at best.  The 2.4GHz band is only capable of somewhere around 574 so you may be getting great results if connected to that radio and getting your reported speeds.

Good luck.  Hope this helps,

  @Crazy4wifi 

BTW, you can try installing the Beta firmware to see if that improves performance.  It will also add VPN client capability so that you can connect you router to third party VPN service providers.  You can find it here:

https://community.tp-link.com/us/home/forum/topic/516928