Xiaomi Redmi Note 9S 128 GB Specifications, Tests and Review

The Xiaomi Redmi Note 9S 128 GB has a height of 165.75 mm, a width of 76.68 mm and a thickness of 8.8 mm. The weight of the phone is 209 g.

The screen size reaches 6.67" 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 9S 128 GB is 2400 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 9S 128 GB is equipped with Qualcomm Snapdragon 720G. 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. The processor frequency indicates how many instructions phone can process in 1 second. The higher the frequency, the better the performance. Standard processor frequency range today is between 1.8 GHz and 2.8 GHz. Xiaomi Redmi Note 9S 128 GB reaches the frequency of 2.3 GHz.

The processor also includes the graphics accelerator Qualcomm ADRENO 618.

The phone´s internal memory capacity is 128 GB. The size of the internal storage determines e.g., how many photos, songs, movies, or applications you can store on your phone. For everyday use and storing photos, songs or movies, this medium-sized internal storage is ideal. The advantage is also a lower price of phones equipped with this storage capacity. Best phones today range from 256 GB to 1 TB. That size is suitable for the most demanding users who shoot a lot of high-resolution photos or videos in 4K. Nevertheless, you'll have to pay extra for these higher capacities. Luckily, most smartphone manufacturers nowadays offer models with different memory sizes to suit every user.

An additional option to increase the storage capacity of this model is to insert a memory card.

RAM memory of the Xiaomi Redmi Note 9S 128 GB is 6 GB. Most powerful phones currently have an operating memory of 12 GB or more, which is especially useful for demanding users such as gaming enthusiasts. Normally, phones nowadays have 6 to 8 GB of RAM, which means that the phone can easily handle normal operation and more demanding applications. Operating memory of less than 4 GB is found in lower-end phones or older models, and they are suitable for low-end users who don't use demanding applications and have the phone more for basic use.

The rear camera of the Xiaomi Redmi Note 9S 128 GB is equipped with 4 lenses, with each lens having a different role in taking pictures. Most common lens you'll see on smartphones is a wide-angle lens, telephoto lens or macro lens. A wide-angle lens is mainly used to capture landscapes and other spatially larger compositions where a wide field of view is needed. A telephoto lens is designed for photographing subjects at a distance and often has an optical zoom. A macro lens is ideal for close-ups and small objects. The resolution of the main lens is 48 Megapixel. Higher resolution does not necessarily mean super high quality photos. Furthermore, it depends on the pixel size but also on other important factors. 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 9S 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. The aperture of main lens reaches F/1.79 value. The best phones have a lens with an aperture of up to F/1.5, where more light can pass through sensor and photos will be of a high quality even in low light conditions. However, lenses with apertures around F/1.8 to F/2.2 are the most common. The lower the number after the slash, the better the photo quality. Some users will also appreciate facial recognition feature, which allows camera to recognise the face of person in 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 119 degree(s). The resolution reaches size of 8 Megapixel. Pixel size in this case is 1.12 μm. Furthermore, the second lens is equipped with aperture of F/2.2.

Third camera
The resolution of third lens is then 5 Megapixel. The pixel size that significantly affects quality of photo is 1.12 μm. Last but not least, third lens is equipped with a lens aperture 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 9S 128 GB has one lens. This number of lenses is standard on most smartphones nowadays. The resolution of front lens reaches 16 Megapixel. Again, it should be noted that resolution is only one of several other significant factors that affect resulting quality of a photo. The pixel size itself is 1 μm. The main lens is also equipped with aperture of F/2.48.

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

The battery size of Xiaomi Redmi Note 9S 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. Talk time, or we can say battery life when making calls, then indicates amount of time your phone will last from a full charge if you are constantly on a call. Xiaomi Redmi Note 9S 128 GB is provided with a talk time about 1980 minutes.

Xiaomi Redmi Note 9S 128 GB supports 4G. 5G connectivity, which is slowly replacing standard 4G connectivity, is still more the preserve of the latest phones.

Basic connectivity standards also include Bluetooth 5.0, making it easy to communicate wirelessly with other devices such as headphones, tablets, speakers and smartwatches.