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Oppo K3 (2019) 256GB vs vivo X21 UD (2018) 128GB: Which is the best?

Created date: 2019-05-24 05:42:17, Updated date: 2021-10-20 18:32:42

Oppo K3 (2019) 256GBvivo X21 UD (2018) 128GB
Oppo K3 (2019) 256GBvivo X21 UD (2018) 128GB

Are you having trouble comparing the differences in features and performance of the "Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", or unsure about their differences in ease-of-use, and wondering which to buy? We did a deep-dive comparison of the features, specs, and capabilities of these two smartphone, and provided our rating of which one was a better buy.

Oppo K3 (2019) 256GBvivo X21 UD (2018) 128GB
Oppo K3 (2019) 256GB

vivo X21 UD (2018) 128GB

General rating:
Holding comfortrating-image2.9
76.0mm x 161.2mm x 9.4mm
rating-image3.2
74.8mm x 154.5mm x 7.4mm
Weightrating-image2.7
191.0g
rating-image3.4
156.2g
Screen sizerating-image4.5
6.5inch
rating-image4.5
6.28inch
Display qualityrating-image4.2
396ppi
rating-image4.2
401ppi
Battery liferating-image3.8
3765.0mAh
rating-image3.4
3200.0mAh
Processing powerrating-image4.6
2.2GHz+1.7GHz×8(8.0-cores)
rating-image4.5
2.2GHz+1.8GHz×8(8.0-cores)
Memory capacityrating-image4.7
8.0GB
rating-image4.5
6.0GB
Storage capacityrating-image4.6
256.0GB
rating-image4.5
128.0GB
Rear camera performancerating-image3.4
16.0MP
rating-image3.0
12.0MP
Front camera performancerating-image3.8
16.0MP
rating-image3.5
12.0MP

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", performance comparison

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB" size comparison. Which to choose?

The size of the body has a big influence on the ease of carrying and one-handed operation. The narrower the width, the easier it is to firmly grasp and hold, but you also have to take into account the device's thickness. Also, if the width and height are smaller, its easier to operate one-handed since its easier to extend your fingers. On the contrary, if the width and height are large, it's difficult to fit in your pocket and is bulky even when put in a bag, and portability is impaired.

The "Oppo K3 (2019) 256GB" has a width of 76.0mm, a length of 161.2mm, and a thickness of 9.4mm. Also, the "vivo X21 UD (2018) 128GB" has a width of 74.8mm, a length of 154.5mm, and a thickness of 7.4mm.

Comparing the width and thickness of the body, the "vivo X21 UD (2018) 128GB" is smaller and more compact compared to the "Oppo K3 (2019) 256GB". For that reason, the "vivo X21 UD (2018) 128GB" is easier to grip firmly and carry one-handed than the "Oppo K3 (2019) 256GB". For that reason, we recommend the "vivo X21 UD (2018) 128GB".

Comparing the width and thickness of the body, there isn't a large difference in size between the "Oppo K3 (2019) 256GB" and the "vivo X21 UD (2018) 128GB". For that reason their one-handed operability, portability, and bulkiness when carried is about the same. That's why I think it's better to compare them in terms of other aspects of performance and functionality.

Comparing the overall size of the two devices, there isn't a big difference in size between the "Oppo K3 (2019) 256GB" and the "vivo X21 UD (2018) 128GB". For that reason the ease of carrying and use with one hand is about the same for both. That's why it is better to compare the two in terms of other aspects of performance and functionality.

ScoreDimensions (width x height x thickness)
Oppo K3 (2019) 256GB58/10076.0mm x 161.2mm x 9.4mm
vivo X21 UD (2018) 128GB64/10074.8mm x 154.5mm x 7.4mm

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", which is more comfortable to hold? Weight comparison

The weight of the device affects hand fatigue and the burden placed upon the wrist. The lighter it is, the longer you'll be able to operate the device without tiring. Also, if the burden placed on the wrist is lower, you'll be able to use the device more comfortably. However if the weight isn't right for you, it could place more of a burden on your body, causing you to feel stress.

The weight of the "Oppo K3 (2019) 256GB" is about 191.0g, and the weight of the "vivo X21 UD (2018) 128GB" is about 156.2g. Comparing the weight of the two devices, the "vivo X21 UD (2018) 128GB" is a considerably lighter smart phone than the "Oppo K3 (2019) 256GB", and there is a difference of about 34.8g. In terms of the burden placed upon your fingers and wrist, the "vivo X21 UD (2018) 128GB" is superior to the "Oppo K3 (2019) 256GB". If you are going for a smart phone that won't lead to hand fatigue even after extended use, and is less likely to place a burden on your fingers, we recommend purchasing the "vivo X21 UD (2018) 128GB" over the "Oppo K3 (2019) 256GB".

ScoreWeight
Oppo K3 (2019) 256GB54/100191.0g
vivo X21 UD (2018) 128GB67/100156.2g

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", whose display is easier to use?

The size of the screen affects usability and screen visibility. A larger screen means larger letters and buttons on apps, so the user is less likely to tap adjacent buttons by mistake. In addition, the user can enjoy a more intense experience when playing games and watching videos.

The "Oppo K3 (2019) 256GB" has a 6.5inch display. Also, the "vivo X21 UD (2018) 128GB" has a 6.28inch display. Comparing the screen size, there is a negligible difference in screen size between the "Oppo K3 (2019) 256GB" and the "vivo X21 UD (2018) 128GB". As a result, the app buttons on both are equally easy to press. We recommend comparing them based on other aspects of performance and functionality.

ScoreDisplay size
Oppo K3 (2019) 256GB90/1006.5inch
vivo X21 UD (2018) 128GB90/1006.28inch

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", which has a clearer display?

Pixel density affects picture quality, and the higher the pixel density, the better the picture quality, which means the user can gain more enjoyment from games and videos. In addition, higher picture quality decreases eyestrain, which means that the user will experience less eye fatigue after prolonged use.

The resolution on the "Oppo K3 (2019) 256GB" is 1080 x 2340, and pixel density is 396ppi. Also, the resolution on the "vivo X21 UD (2018) 128GB" is 1080 x 2280, and pixel density is 401ppi. Comparing the pixel count, the difference in pixel density between the "Oppo K3 (2019) 256GB" and the "vivo X21 UD (2018) 128GB" is negligible. As a result, they are both evenly matched in terms of picture quality and easiness on the eyes. Therefore, we recommend comparing them based on other aspects of performance and functionality.

ScorePixel density
Oppo K3 (2019) 256GB84/100396ppi
vivo X21 UD (2018) 128GB84/100401ppi

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", a summary of the differences in battery life

Battery performance greatly affects battery life, but greater battery capacity does not necessarily mean greater battery life, since battery efficiency should also be considered. Bigger screens and higher CPU performance will mean the batteries are depleted more quickly.

The "Oppo K3 (2019) 256GB" is 3765.0mAh, and the "vivo X21 UD (2018) 128GB" is 3200.0mAh. Regarding battery capacity, the "Oppo K3 (2019) 256GB" has greater battery capacity than the "vivo X21 UD (2018) 128GB", with a 565mAh difference. If battery is a priority, then the "Oppo K3 (2019) 256GB" is recommended over the "vivo X21 UD (2018) 128GB".

ScoreBattery capacity
Oppo K3 (2019) 256GB76/1003765.0mAh
vivo X21 UD (2018) 128GB68/1003200.0mAh

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", which has better CPU?

CPU performance affects the ability to process programs, and the ability to process programs is determined by the product of the number of cores in the CPU and the CPU frequency. The higher this performance is, the more smoothly apps and games will run, and with low performance apps and games become heavy and stress is experienced.

The "Oppo K3 (2019) 256GB"'s CPU is a Qualcomm SDM710 Snapdragon 710, with performance measured at 2.2GHz+1.7GHz×8(8.0-cores). Also, the "vivo X21 UD (2018) 128GB"'s CPU is a Qualcomm SDM660 Snapdragon 660, with performance measured at 2.2GHz+1.8GHz×8(8.0-cores). Comparing CPU performance, there is almost no difference in the specs of the "Oppo K3 (2019) 256GB" and the "vivo X21 UD (2018) 128GB". For that reason the level of smoothness felt when using apps and comfortable handling of games is about the same. For that reason it is better to compare them in terms of other aspects of performance and functionality.

ScoreCPU specs
Oppo K3 (2019) 256GB92/1002.2GHz+1.7GHz×8(8.0-cores)
vivo X21 UD (2018) 128GB90/1002.2GHz+1.8GHz×8(8.0-cores)

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", what's the difference in memory capacity?

RAM affects multitasking ability and the stability of apps. The larger the amount of RAM is, the more stability there will be even in situations where multiple apps are running simultaneously, allowing for comfortable use. In addition, animation will be more smooth, and apps will be less likely to freeze or crash. Also, without sufficient RAM, there are games you won't be able to run, so it is necessary to be careful.

The weight of the "Oppo K3 (2019) 256GB" is 8.0GB and the weight of the "vivo X21 UD (2018) 128GB" is 6.0GB. Comparing the devices in terms of RAM, there is almost no difference in the amount of RAM of the "Oppo K3 (2019) 256GB" and the "vivo X21 UD (2018) 128GB". For that reason they have about the same level of multitasking performance and 3D game and VR smoothness. That's why it is better to make a comparison in terms of other aspects of performance and functionality.

ScoreRAM size
Oppo K3 (2019) 256GB93/1008.0GB
vivo X21 UD (2018) 128GB90/1006.0GB

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", which has more data storage?

Storage capacity affects the amount of data that is capable of being stored. The larger the storage capacity, the more pictures you can take and the more applications you can install. In addition, if your smartphone accepts SD cards, then you can increase its storage capacity. However, there are performance related drawbacks, including a slower data transfer rate than the primary memory, and you cannot transfer all your data on the card, so be warned.

The data storage capacity of the "Oppo K3 (2019) 256GB" is 256.0GB. Also the "vivo X21 UD (2018) 128GB" is 128.0GB. Regarding storage capacity, there is a negligible difference in storage capacity between the "Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB". As a result, you can save roughly the same amount of pictures, and install roughly the same amount of applications, on either phone. You are better off comparing them based on other aspects of performance and functionality.

ScoreStorage size
Oppo K3 (2019) 256GB91/100256.0GB
vivo X21 UD (2018) 128GB90/100128.0GB

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB" rear camera performance comparison. Which has a higher resolution?

One factor that determines the performance of the exterior camera located on the back of the device (the rear/back camera) is the pixel count. The larger the pixel count, the higher the resolution of the pictures you can take, and the cleaner the pictures will look when printed.

"Oppo K3 (2019) 256GB" has a 16.0MP main camera. Also, "vivo X21 UD (2018) 128GB" has a 12.0MP main camera. Comparing rear camera performance, the "Oppo K3 (2019) 256GB" has a higher pixel count than the "vivo X21 UD (2018) 128GB", with a roughly 4MP difference. As a result, the "Oppo K3 (2019) 256GB" is better able to take high quality landscape pictures than the "vivo X21 UD (2018) 128GB", and the pictures will look cleaner when printed. Therefore, we recommend the "Oppo K3 (2019) 256GB".

ScoreRear-camera resolution
Oppo K3 (2019) 256GB68/10016.0MP
vivo X21 UD (2018) 128GB59/10012.0MP

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", whose front camera has a better picture quality?

One factor that determines the performance of the exterior camera located on the front of the device (the in/front camera) is the pixel count. The larger the pixel count, the higher the resolution of the pictures you can take, and the cleaner the pictures will look when printed.

"Oppo K3 (2019) 256GB" has an 16.0MP front camera and "vivo X21 UD (2018) 128GB" has an 12.0MP front camera. Comparing rear camera performance, the front camera of the "Oppo K3 (2019) 256GB" has a higher pixel count than the "vivo X21 UD (2018) 128GB", with a roughly 4MP difference. As a result, the "Oppo K3 (2019) 256GB" is better able to take high quality selfies than the "vivo X21 UD (2018) 128GB", and the pictures will look cleaner when printed. Therefore, we recommend the "Oppo K3 (2019) 256GB".

ScoreFront-camera resolution
Oppo K3 (2019) 256GB75/10016.0MP
vivo X21 UD (2018) 128GB70/10012.0MP

"Oppo K3 (2019) 256GB" and "vivo X21 UD (2018) 128GB", performance comparison by specification sheet

Oppo K3 (2019) 256GBvivo X21 UD (2018) 128GB
ImageOppo K3 (2019) 256GBvivo X21 UD (2018) 128GB
MakerOppovivo
Release date2019-052018-03
ColorBlack/Nebula Purple/Morning WhiteBlack/Ruby Red
OSAndroidAndroid
Dimensions (width x height x thickness)76.0mm x 161.2mm x 9.4mm74.8mm x 154.5mm x 7.4mm
Weight191.0g156.2g
Display size6.5inch6.28inch
Display typeAMOLEDSuper AMOLED
Screen resolution (width x height)1080 x 23401080 x 2280
Pixel density396ppi401ppi
Battery capacity3765.0mAh3200.0mAh
ChipsetQualcomm SDM710 Snapdragon 710Qualcomm SDM660 Snapdragon 660
CPU specs2.2GHz+1.7GHz×8(8.0-cores)2.2GHz+1.8GHz×8(8.0-cores)
RAM size8.0GB6.0GB
Storage size256.0GB128.0GB
Rear-camera resolution16.0MP12.0MP
Front-camera resolution16.0MP12.0MP

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