If you’re finding that a website containing a lot of JavaScript is performing badly on a particular browser/device you can run the Browserbench.org Speedometer. That will check the performance of that device and you can then compare it against some known results.
Here are a few Browserbench.org Speedometer results from devices I had access to from September 2019 to April 2022.
| Device | Processor | OS | Browser | Result |
|---|---|---|---|---|
| iPhone SE (2020) | A13 Bionic | iOS 15.4.1 | Safari 15.4 | 190 |
| iPhone SE (2020) | A13 Bionic | iOS 13.4.1 | Safari 13 | 152 |
| Lenovo P320 | Xeon E3-1245 v6 @3.7 GHz | Windows 10 Pro 21H2 | Edge 106.0.1370.47 | 103 |
| Lenovo P320 | Xeon E3-1245 v6 @3.7 GHz | Windows 10 Pro 1809 | Chrome 77.0.3865.90 | 98.2 |
| MacBook Pro Mid 2012 | Core i7 2.3 GHz | macOS Ventura 13.1 | Edge 109.0.1518.70 | 90.8 |
| MacBook Pro Mid 2012 | Core i7 2.3 GHz | macOS Ventura 13.1 | Safari 16.2 | 86.9 |
| MacBook Pro Mid 2012 | Core i7 2.3 GHz | macOS Ventura 13.1 | Firefox 109.0 | 80.0 |
| Lenovo P320 | Xeon E3-1245 v6 @3.7 GHz | Windows 10 Pro 1809 | Firefox 68.02 | 80.6 |
| MacBook Pro Mid 2012 | Core i7 2.3 GHz | macOS Catalina 10.15.7 | Safari 15.4 | 78.3 |
| MacBook Pro Mid 2012 | Core i7 2.3 GHz | macOS Catalina 10.15.7 | Firefox 99.0.1 | 77.37 |
| MacBook Pro Mid 2012 | Core i7 2.3 GHz | Mac OS X Mojave 10.14.6 | Safari 13.1 | 70.7 |
| MacBook Pro Mid 2012 | Core i7 2.3 GHz | macOS Catalina 10.15.7 | Edge 101.0.1210.32 | 62.6 |
| MacBook Pro Mid 2012 | Core i7 2.3 GHz | Mac OS X High Sierra 10.13.6 | Safari 13 | 60.9 |
| Lenovo P320 | Xeon E3-1245 v6 @3.7 GHz | Windows 10 Pro 1809 | Edge 44.17763.1.0 | 58.9 |
| MacBook Pro Mid 2012 | Core i7 2.3 GHz | Mac OS X Mojave 10.14.6 | Firefox 75 | 57.1 |
| iPhone SE | A9 APL1022 | iOS 13.1.2 | Safari | 50.2 |
| MacBook Pro Mid 2012 | Core i7 2.3 GHz | Mac OS X High Sierra 10.13.6 | Firefox 69.01 | 47.41 |
| iPhone SE | A9 APL1022 | iOS 12.4 | Safari | 42.7 |
| iPhone 6 | A8 APL1011 | iOS 12.4.1 | Safari | 24.7 |
| iPhone 6 | A8 APL1011 | iOS 12.4.1 | Firefox Focus | 25.5 |
| iPhone 6 | A8 APL1011 | iOS 12.4.1 | Opera | 16.58 |
| ASUS Nexus 7 tablet K008 | Qualcomm Snapdragon S4 Pro | Android 6.0.1 | Chrome 75.0.3770.101 | 7.93 |
As you can see on the same hardware, the choice of browser and OS version can make a big difference.
