Xiaomi Redmi Note 9 128 GB Specifications, Tests and Review

The Xiaomi Redmi Note 9 128 GB has dimensions 162.3 mm × 77.2 mm × 8.9 mm. Its weight is 199 g.

The screen size reaches 6.53" inches. With a large display, phone offers a great experience for watching videos, playing games and reading. The best phones today are 6.5'' or more. They have the advantage of a large display area that allows you to see more content than with conventional display sizes. LCD displays are currently taking a back seat. This is mainly due to higher power consumption. In addition, they have the disadvantage of lower colour contrast, which can be reflected e.g. in the resulting photos. On the other hand, phones with LCD displays are in general cheaper than those with OLED technology.

Display Resolution of Xiaomi Redmi Note 9 128 GB is 2340 x 1080 pixels. A higher display resolution is a prerequisite for a sharper image. The standard for mid-range phones today is a Full HD resolution of 1920 × 1080 px. Cheaper phones, which usually have a smaller diagonal, have an HD resolution of 1280 × 720 px. Smaller resolutions can only be found in older models. Best phones, on the other hand, have a 4K resolution of 3840 x 2160 px.

Xiaomi Redmi Note 9 128 GB is supplied with MediaTek Helio G85. The number of processor cores is 8. It is a number of cores that plays an important role in evaluating the performance of phone as it is responsible for computing operations. Smartphones already commonly have a core count of around 4 to 8. Multi-core processors can perform better and reduce the processing time of a request to a minimum, which is reflected in the responsiveness of the phone, e.g. in the speed of opening applications. Another important parameter is the processor frequency, which indicates how many instructions the phone can process in one second. Similar to refresh rate, the higher the number, the faster the phone responds. Processor frequency of phone Xiaomi Redmi Note 9 128 GB is 2 GHz. As standard today, you'll find this value between 1.8 GHz and 2.8 GHz.

The processor also includes the graphics accelerator ARM G52 MC2.

One of the most important parameters for user´s decision is often internal memory capacity. The larger it is, the more apps, photos, movies and other files your phone can store. This phone has 128 GB storage. It is currently the most common storage size among today´s smartphones. The capacity is perfectly adequate for the average user. It will allow you to store thousands of photos, high-resolution videos, dozens of apps and several games on your phone. But if you're one of those really demanding users and you use your phone to shoot 4K videos etc., then you should rather pay extra to have a larger storage of 256 GB or more. Nowadays, you can usually find one phone model on the market with several different memory sizes. This allows each user to choose what suits them best.

For this model it is possible to increase the storage size by inserting a memory card.

Size of the RAM memory tells us how powerful the phone is. Xiaomi Redmi Note 9 128 GB is equipped with 4 GB. Commonly today you will find phones with 6 to 8 GB of RAM. This means that the phone can easily handle normal operation and more demanding applications or games. Higher RAM of 12 GB can be found in best phones on market and are ideal especially for avid gamers. On the other hand, operating memory below 4 GB is more of an issue with lower-end phones and older models. However, even they will find their fans among less demanding users, who don´t want to spend much on buying new phone.

The rear camera of the phone Xiaomi Redmi Note 9 128 GB has 4 lenses. Today's modern phones usually have several rear lenses. The most common are macro lens, telephoto lens and wide-angle lens. Each is used to capture the perfect photo - macro lens is designed for close-up photography, telephoto lens, often equipped with an optical zoom, is for photos of objects in distance, and wide-angle lens captures larger areas where you need a wider field of view. The resolution of main lens is 48 Megapixel. Nonetheless, resolution alone does not necessarily mean a good photo. Therefore, you should look at other parameters such as lens aperture or pixel size. Pixel size is typically around 0.8-1.8 μm in better mobile phones. The higher the value, the better the quality of the resulting photo should be. In the case of main lens, the pixel size reaches 0.8 μm.

The size of the phone's sensor is also among the parameters that affect quality of the photo. In case of Xiaomi Redmi Note 9 128 GB, it is 1/2". Focus mainly on the value after the slash, where the higher it is, the better photo quality will be. Another important factor is the aperture, which in this case is F/1.79 and determines how much light passes through the sensor. Best phones have an aperture of up to F/1.5. But the most common lenses today are F/1.8 to F/2.2. In this case, the lower the number after the slash, the higher the photo quality. Many people will also benefit from the facial recognition feature. In translation it means the camera can recognise face of person in the frame and automatically focus on it.

Second camera
The second lens of rear camera is designed as Ultra wide-angle lens. The field of view of second lens reaches 118 degree(s). The resolution reaches size of 8 Megapixel. Pixel size in this case is 1.2 μm. In addition, this lens also features lens aperture of F/2.2.

Third camera
The resolution of third lens is then 2 Megapixel. The pixel size that significantly affects quality of photo is 1.75 μm. The aperture reaches size of F/2.4.

Fourth camera
The resolution of fourth rear camera reaches 2 Megapixel. The pixel size is 1.75 μm. Lens aperture value then reaches F/2.4.

Front camera
The front camera of phone Xiaomi Redmi Note 9 128 GB has one lens. This number of lenses is standard on most smartphones nowadays. The lens is equipped with 13 Megapixel. However, do not forget there are other factors than resolution having impact on the final quality of front camera photos. The pixel size itself is 1.12 μm. The main front lens also achieves F/2.25. As for the field of view of main lens of front camera, it reaches 74 degree(s).

The facial recognition feature is just a nice cherry on top.

The battery size of Xiaomi Redmi Note 9 128 GB is 5020 mAh. Nevertheless, battery capacity is not the only factor that affects the phone's battery life. For example - the size of the display, the performance of the processor, the use of data functions and, of course, the intensity of use of phone in general all have a significant impact on battery life. Standard for most smartphones today is a battery capacity of around 4500 to 5000 mAH. Phones with this battery size usually guarantee a phone life of at least 1 day. Older or cheaper smartphone models can then reach battery capacities typically around 2500 mAH and below. With this capacity, you may find that if you use your phone heavily, you may need to recharge your phone during the day. The phone Xiaomi Redmi Note 9 128 GB will last one charge with constant phone calls 1980 minutes.

Standard 4G connectivity is currently being replaced by 5G, but is still the preserve of the latest phones. Xiaomi Redmi Note 9 128 GB supports 4G. 3G connectivity is now only found in the oldest phones. The operating system in the case of this model is Android 10.

Bluetooth 5.0 must not be missing from the basic package. It makes it easy to connect wireless headphones to your phone, connect your phone to your TV, tablet, speaker and more.