Repeater vs Router / Wireless vs Wired

Hi Guys I am currently new in the FTTH sector. I am getting a very satisfactory speed of 50mbps upload and download at my house. I have connected the primary modem to a D-Link DIR-615 Wireless-N300 Router. This is my primary router . I also have a Netgear repeater (Netgear EX2700 N300 Wi-Fi Range Extender ) connected to boost up the range.
Now what is happening is that my range is fine in all rooms- but the speed is dropping consistantly (around 20-25 mbps in other rooms). From what I have heard, this is due to the repeater . The speed in the room with the primary router is still fantastic.
My network guy told me to get a new router and has given me a cat5 cable. He says connecting a new router to the primary router will solve my speed drop issue.
Is there anyone who can walk me through the idea? We are heavy streaming people and at times have three screens blasting Amazon prime/netflix in tandem. Can anyone give me a good solution. I also have an old Asus rt n10+ n router lying around, though I dont mind buying a new router.
Anyone?

@dryash this needs a bit of familiarity with networking. Are you comfortable doing that?

I am a novice but I'm a fast learner 🙂 try me

Its late today. So l will just link you to Amit Agarwal's write up on this subject for today. Read it up and follow it to the T. After that, if its not working we can take up tomorrow. Here's the link:

Thank you 🙂

So the best way seems to be connecting to another router through an Ethernet cable

Yes. In this way, the speed wouldn't reduce drastically.

Great. Just two questions.

1. The modem I have now. D-Link (posted above) is good enough? It's quite cheap so I can buy a new one.
2. My internet guy is providing me with a cat 5 line. Do I need to upgrade to my own cat 6 or should I stay on cat 5 for now. Speed of my ftth is 50mbps.

faster is always better. if you can get cat6 by paying a bit extra, definitely go for it.

And does the extra router need to be the basic one?since there are going to be two anyway

if the area to be covered by the extender is quite small, a basic one should suffice. though for long term, it might be a good idea to get a high speed dual band router. but once the wiring is done, you can always upgrade. you can also use the wireless extender you already have as it should also have ethernet port.

I have a repeater which has a LAN port..I can't use that as an extender with wires can I?

ok. now that i checked it, the ethernet port on the Netgear wireless extender seems to be outgoing and not incoming. so it probably cannot be connected to the ethernet coming from your primary router. at least that's what it looks like.

@dryash u r getting low speeds due to 2.4g band.
The router u using it supports 2.4g band.
The 2.4g band is provides good range but speeds are low.
I UPGRADED my Airtel connection to FTTH last month.I faced same problem.
Then I bought TP-Link RE305 AC1200 Dual-Band Wi-Fi Range Extender
Now I m getting 100Mbps speed every corner of my home and I m getting very stable connection and speed.

I tested speeds on both bands.
2.4g 30Mbps to 45Mbps
5g always getting 100Mbps both UP and DOWN

Hi. If possible, get the use of Ethernet (Cat 5e or Cat 6).

If not possible,

Buy another cheap router which can be used as Access Point and connect that to the main router with the ethernet.

If ^ not possible,

Buy a Repeater.