1) Internal modem and antennas
Every phone can make and receive calls of course, and manage the flow of data to and from your device, but they don't all do it equally well. The modem inside your smartphone is responsible for all this wireless traffic, and it's one of the specs that's worth looking out for.
The choice of modem dictates the maximum upload and download speeds you can expect on and off Wi-Fi, and which networks you can connect to while out of the country, and even whether or not a phone is able to include dual-SIM support or not. Better modems can work well on less power, meaning more battery life.
More antennas typically equates to faster speeds and a stronger signal. Of course, the top-end phones will only get the top-end cellular speeds
***
2) IP rating
The IP rating on a phone (or any other piece of gadgetry) refers to how well it can repel dust and water. IP simply stands for International Protection (or sometimes Ingress Protection), and is managed by the International Electrotechnical Commission.
The first digit after the IP is "solid particle" (dust) protection. As far as smartphones are concerned, it goes from 0, which is no protection at all, to 6, which is dust tight and means no particles can get inside the casing at all.
The second digit concerns "liquid ingress" (water) protection. For phones, you're looking at anywhere from a 0 (no protection) to an 8 (continuous immersion in water). Higher numbers are sometimes used (9K means protection against high temperature water gets), but for phones, IP68 is the gold standard.
However, manufacturers do have some flexibility in defining what the "8" in IP68 actually means, beyond continuous immersion: On every phone spec sheet you should see a mention of a depth and a time limit that the phone can withstand.
Smartphone makers are under no obligation to specify IP ratings, and may just use terms like "splashproof" or "waterproof" -- check the small print to find out exactly what this means. The good news for consumers is that most newer phones now offer some relatively good dust and waterproofing standard.

3) Charging speeds
If you simply plug your phone into the wall every night and forget about it, you might never have given much thought to how quickly its battery is filling up again -- as long as it's on 100 per cent by the morning, you're good to go. It's when you're dashing from place to place or perhaps only have a quick 10 minutes to juice up your phone that charging speed (and wireless charging speed) starts to matter.
How fast a phone charges depends on the way the phone is built, and the power of the mains or wireless adaptor you're using with it. You need both a fast-charging phone and a fast-charging adaptor to get your handset juiced up as quickly as possible -- as you'll know if you've ever tried to charge your phone from a laptop's USB port.
Look for the power of your charger, measured in watts (W), which is the current (often listed as amps or A) multiplied by the voltage (V). Also take note of the charging rate listed on the phone's specs. Manufacturers like to deploy a bunch of proprietary fast charging standards, and this infographic gives you some idea about how they compare.
Unless you're using a dodgy charger from some unknown brand, you're not going to blow up your phone by using a charger that's too powerful: Today's handsets include safety measures to stop that from happening.
***
4) AI engine
If you watched any of the major phone launches of 2018, you'll have seen reference to processor chips augmented with extra artificial intelligence powers -- and AI is indeed something that's worth looking out for the next time you're choosing a phone.

The internal architecture varies between manufacturers, but the basic idea is the same. These AI chips (or subsets of chips) are designed to handle the sorts of calculations needed for machine learning, in the same way that graphics chips are designed to handle the sorts of calculations needed for pushing pixels to a display.

One of the easiest examples to understand Artificial Intelligence is image recognition: when your. smartphone can spot which of your photos includes a dog, or being able to tell when you're shooting a close-up flower (so the camera app can intelligently adjust the camera settings to match). Being able to quickly recognise your voice through AI is another example.
http://www.infinix.club/ng/forum/687/846643