My experience tells me that the bigger 'home LTE gateway' usually can receive better signal. I guess it's due to higher power gain (since it's power source is directly from adapter, so why not?).

This is why they introduce LTE-A to ease the congestion.

So I assume you're using a LTE-A capable device?
Well I think you have to sync up your expectation with Digi. If i am not wrong, the quality assurance set by them is 10mbps for 80% of the connected time as I read from some recent press release (you have to check with them personally for more accurate information).
But I do acknowledge that sometimes at the fringe of the coverage area, your phone will tend to jump between 3G and 4G.

It depends on the direction of the telco.
Take a look at Umobile, the network is like forever 3G.

It would depend on the connection from domestic to the particular service/server too. Let's say you have 10mbps bandwidth from your mobile to ISP, and from ISP there is only 1mbps bandwidth to yahoo, then the speed will still stick to 1mbps at best. Of course the more people accessing the particular service (yahoo in this case for example), the slower it get despite that you have a lot of bandwidth to your local ISP.

I guess not. The main purpose of band 8 in Digi is only to solve the indoor cellular coverage as well as to cover more area for rural places. Plus the allocated bandwidth for band 8 for Digi is merely 5Mhz. It’s really not enough for super speed use.

You must know that while Digi is providing the internet to you, but it does not mean the speed is consistent across services. For example, there might be only 10mbps downlink rate from Digi to oversea server for a gaming service although your local downlink can be more than 40-50mbps. That particular ‘pipe’ to the service might be congested because a lot of people in the network are competing for it. And if the service (like Netflix) hosts its content server or service in Malaysia, then you will be able to enjoy much better speed (but also subject to the number of users to use it at the same time).

What is the speed?

The 1mbps claim is for real or it’s simply due to congestion or subject to sharping due to fair usage policy?

Maybe it’s slow to some servers only. You try to do a Speedtest against the Digi server.

What you would like to do with the NAT?
As far as I know all terminals connected to Digi’s LTE network is already NAT-ed at its level and each will be given private IP.

The type of device matters too.

If the device supports the feature, it should work automatically.

Why don’t you question if the avast virus definition server is down at the moment?

A dedicated cellular modem router will be better. Mifi usually can not stand the stress of long hour usage.

You mean the B618?

Then what’s the performance you want? Wireless internet is never consistent and you can’t just label it as congestion just because the speed is not up to your desire.

How do you conclude it’s a congestion? Usually the Speedtest is just testing against the local server (most of the time) and if the service you’re accessing is hosted at overseas (assumes there is no co-located content served locally or regionally), most likely the outward link is the bottleneck.

okay, let’s say you have a connection throughput of 80mbps from your connected client to Digi’s 4G network, and from Digi’s network to YouTube server is only rated at 1.5mbps and from digi’s Network to Singtel’s server is 35mbps at the same point of time, when you do a an access to YouTube server, the bottleneck would be the link between digi and YouTube server, and when you do a speedtest to Singtel server via speedtest app, it will show you much higher throughput because digi simply has much better throughput link from its network to singtel.

Therefore it’s not really accurate to say it’s congestion of the 4G network at your area at that point of time, it might be due to ‘congestion’ of its back haul to certain services.

If you don’t use DNS at all, you won’t be able to access anything on the internet.