Both OnePlus 9 and Realme X2 (8GB RAM + 128GB) comes with same RAM. In terms of display resolution, OnePlus 9 has better resolution of 2400 x 1080 than Realme X2 (8GB RAM + 128GB) which has resolution of 2340 x 1080. Both have the same amount of internal memory.
| Name | OnePlus 9 | Realme X2 (8GB RAM + 128GB) | 
| RAM | 8 GB | 8 GB | 
|---|---|---|
| Display | 6.55 in | 6.4 in | 
| Internal Memory | 128 GB | 128 GB | 
| Battery | 4500 mAh | 4000 mAh | 
| Camera | 50 MP + 48 MP + 2 MP Triple | 64 MP Quad | 
| Price | Rs. 19490 | Rs. 13499 | 
The launch Date of the first phone is March 23, 2021 . The cost of OnePlus 9 is Rs. 19490. The launch Date of the second phone is December 20, 2019. The cost of Realme X2 (8GB RAM + 128GB) is Rs. 13499.
OnePlus 9 has larger screen size of 6.55 inches in comparison to Realme X2 (8GB RAM + 128GB)'s 6.4 inch screen. OnePlus 9 has Screen type where as Realme X2 (8GB RAM + 128GB) has Super AMOLED Screen type. Realme's phone has display density of 402 PPI & OnePlus's phone has only 396 PPI display density. In terms of screen to body ratio, Realme's phone has better screen to body ratio of ~ 91.9% than OnePlus's phone ~ 89.7%. OnePlus 9 has 20:9 aspect ratio where as Realme X2 (8GB RAM + 128GB) has 19.5:9 aspect ratio.
Both mobiles come with 8 GB RAM and both have same Internal Memory of 128 GB.
Realme X2 (8GB RAM + 128GB)'s 64 MP Quad Rear Camera outclasses OnePlus 9's 50 MP + 48 MP + 2 MP Triple Rear Camera in terms of resolution. Realme X2 (8GB RAM + 128GB) will be better choice if you're looking to click lot of selfies as it has better 32 MP Front Camera in comparison to OnePlus 9's 16 MP Front Camera.
Both the phones has Android Operating System but the first one runs on version 11 and the second one on 9.0 version.
| Name | OnePlus 9 | Realme X2 (8GB RAM + 128GB) | 
| General | ||
| Model | 9 5G | X2 | 
| Sim Type | Dual Sim, GSM+GSM | Dual Sim, GSM+GSM | 
| Dual Sim | Yes | Yes | 
| Sim Size | Nano+Nano SIM | Nano+Nano SIM | 
| Device Type | Smartphone | Smartphone | 
| Release Date | March 23, 2021 | December 20, 2019 | 
| Design | ||
| Dimensions | 73.9 x 160 x 8.1 mm | 75.2 x 158.7 x 8.6 mm | 
| Weight | 183 g | 182 g | 
| Display | ||
| Type | Color Fluid AMOLED (16M Colors) | Color Super AMOLED Screen (16.7M) | 
| Touch | Yes | Yes | 
| Size | 6.55 inches, 1080 x 2400 pixels, 120 Hz | 6.4 inches, 1080 x 2340 pixels | 
| Aspect Ratio | 20:9 | 19.5:9 | 
| PPI | ~ 396 PPI | ~ 402 PPI | 
| Screen to Body Ratio | ~ 89.7% | ~ 91.9% | 
| Glass Type | Corning Gorilla Glass 6 | |
| Features | Reading Mode, Night Mode, Vibrant Color Effect, HDR | Corning Gorilla Glass 5 | 
| Notch | Yes, Punch Hole | Yes, Water Drop Notch | 
| Memory | ||
| RAM | 8 GB | 8 GB | 
| Storage | 128 GB | 128 GB | 
| Storage Type | UFS 3.1 | |
| Card Slot | No | Yes, upto 256 GB | 
| Connectivity | ||
| GPRS | Yes | Yes | 
| EDGE | Yes | Yes | 
| 3G | Yes | Yes | 
| 4G | Yes | Yes | 
| 5G | Yes | |
| VoLTE | Yes, Dual Stand-By | Yes, Dual Stand-By | 
| Wifi | Yes, with wifi-hotspot | Yes, with wifi-hotspot | 
| Bluetooth | Yes, v5.2, A2DP, LE, aptX HD, LDAC, AAC | Yes, v5.0, A2DP, LE | 
| USB | Yes, USB-C v3.1 | Yes, USB-C v2.0 | 
| USB Features | USB on-the-go, USB Charging | USB Tethering, USB on-the-go, USB Charging | 
| Extra | ||
| GPS | yes with A-GPS | Yes, with A-GPS, GLONASS, GALILEO, BDS | 
| Fingerprint Sensor | Yes, In Display | Yes, In Display | 
| Face Unlock | Yes | Yes | 
| Sensors | Accelerometer, Electronic Compass, Gyroscope, Ambient Light Sensor, Proximity Sensor, Sensor Core, Flick-detect Sensor | Accelerometer, Gyro, Proximity, Compass | 
| 3.5mm Headphone Jack | No | Yes | 
| NFC | Yes | |
| Extra Features | Dolby Atmos, UFS 2.1 | |
| Camera | ||
| Rear Camera | 48 MP ƒ/1.8 (Main) 50 MP ƒ/2.2 (Ultra Wide) 2 MP Monochrome | 64 MP ƒ/1.8 (Ultra Wide) 8 MP ƒ/2.3 (Wide Angle) 2 MP ƒ/2.4 (Macro) Macro 2 MP ƒ/2.4 Portrait | 
| OIS | Yes | |
| Auto Focus | Yes | Yes | 
| Features | Co-Developed by Hasselblad, Nightscape, Super Macro, UltraShot HDR, Smart Scene Recognition, Portrait mode, Pro mode, Panorama | HDR, Panorama, Electric Image Stabilization | 
| Video Recording | 8K @ 30 fps UHD, 4K @ 30/60 fps UHD, 1080p @ 30/60 fps FHD | 4K @ 30 fps UHD, 1080p @ 30/60 fps FHD, 720p @ 30/60 fps HD | 
| Flash | Yes, Dual LED | Yes, LED | 
| Front Camera | 16 MP ƒ/2.4 Punch Hole, Screen Flash | 32 MP ƒ/2 (Main) | 
| Front Video Recording | 1080p @ 30 fps FHD | 1080p @ 30 fps FHD | 
| Technical | ||
| OS | Android v11, upgradable to v12 | Android v9.0 (Pie) | 
| Chipset | Qualcomm Snapdragon 888 | Qualcomm Snapdragon 730G | 
| CPU | 2.84 GHz, Octa Core Processor | 2.2 GHz, Octa Core Processor | 
| Core Details | Octa-core (1x2.84 GHz Kryo 680 & 3x2.42 GHz Kryo 680 & 4x1.80 GHz Kryo 680 | 2x2.2 GHz Kryo 470 Gold & 6x1.8 GHz Kryo 470 Silver | 
| GPU | Adreno 660 | Adreno 618 | 
| Java | No | No | 
| Browser | Yes, supports HTML5 | Yes, supports HTML5 | 
| Multimedia | ||
| Yes | Yes | |
| Music | MP3, AAC, AAC+, WMA, AMR-NB, AMR-WB, WAV, FLAC, APE, OGG, MID, M4A, IMY, AC3, EAC3, EAC3-JOC, AC4 | 3GP, ASF, AVI, DAT, FLV, M2TS, MKV, MOV, MP4, MPG, MTS, RMVB, TS, VOB, WEBM, WMV | 
| Video | MKV, MOV, MP4, H.265(HEVC), AVI, WMV, TS, 3GP, FLV, WEBM | 3GA, AAC, AMR, APE, FLAC, IMY, M4A, MIDI, MKA, MP3, OGG, QCP, WAV, WMA, WMV | 
| FM Radio | Yes | No | 
| Document Reader | Yes | Yes | 
| Battery | ||
| Type | Non-Removable Battery | Non-Removable Battery | 
| Size | 4500 mAh, Li-Po Battery | 4000 mAh, Li-Po Battery | 
| Fast Charging | Yes, Warp Charge 65T | Yes, 30W VOOC Flash Charge 4.0 |