OpenVPN has long been the go-to protocol for users who want a balance of security and compatibility. It works on nearly every platform, it’s been audited extensively, and it holds up well under scrutiny. The trade-off has always been speed. Compared to newer protocols like WireGuard, standard OpenVPN can feel sluggish, especially on Windows.
IPVanish is trying to close that gap. The company announced a new feature called High-Speed Mode for its Windows app, built on OpenVPN Data Channel Offload (DCO). The claim is significant: up to 196% faster download speeds and up to 101% faster upload speeds compared to standard OpenVPN over UDP, based on internal testing. A separate upgrade to the AES-256-GCM cipher also cuts average connection times by 32%.
For everyday users, this matters because OpenVPN DCO doesn’t change the protocol itself. You still get the same encryption and security guarantees. What changes is how Windows handles the encrypted traffic under the hood, and that difference is substantial.
What OpenVPN DCO actually does
Standard OpenVPN routes encrypted traffic through the VPN application before passing it to the operating system and then on to the network. Every handoff between the app layer and the OS adds a small amount of overhead. When you’re doing something bandwidth-intensive, those small costs add up fast.
OpenVPN DCO moves the data handling closer to the Windows networking layer, cutting out unnecessary back-and-forth between the application and the kernel. The result is less CPU usage, lower latency, and higher throughput, all without touching the underlying cryptography.
IPVanish calls its implementation High-Speed Mode, and it’s available now in the latest version of the Windows desktop app. The benefits include:
- Lower VPN latency
- Faster download and upload speeds
- Reduced CPU overhead during active connections
- More responsive performance during video calls, gaming, and large file transfers
The speed numbers and how they were tested
IPVanish’s engineering team tested standard OpenVPN against OpenVPN DCO across four server locations: New York, London, Berlin, and Tokyo. Each location was tested three times per day over three consecutive days, giving nine data points per location for each configuration.
The average results across nearly every test run showed OpenVPN DCO consistently ahead of standard OpenVPN. Here’s how the numbers broke down by connection type:
- OpenVPN TCP: up to 131% faster downloads, up to 34% faster uploads
- OpenVPN UDP: up to 196% faster downloads, up to 101% faster uploads
As with any speed test, real-world results depend on your hardware, your base internet connection, and your distance to the VPN server. But the consistency across locations and time slots suggests these gains are genuine, not cherry-picked outliers.
The cipher upgrade: AES-256-GCM replaces AES-256-CBC
Alongside DCO, IPVanish also updated the Windows OpenVPN implementation to use AES-256-GCM instead of AES-256-CBC. The practical difference is that GCM combines encryption and integrity checking in a single, more efficient operation, while CBC handles them separately. This doesn’t weaken security in any meaningful way. Both are considered strong. But GCM is faster to compute, which is why the switch shaved 32% off average connection times in testing.
For users who notice a slow VPN handshake when connecting, this update alone is worth having.
Who will notice the difference most
OpenVPN DCO improves performance across the board, but the gains are most obvious during activities that demand sustained throughput or low latency. You’ll likely feel the biggest difference if you regularly:
- Stream 4K or HDR video over a VPN connection
- Download large game updates or software packages
- Upload files to cloud storage
- Join video calls while connected to a VPN
- Play online multiplayer games where ping matters
- Work remotely through a VPN all day
If you’ve stuck with OpenVPN because you trust it, but found yourself frustrated by its speed compared to WireGuard, this update gives you a reason to revisit that choice.
One compatibility note worth knowing
High-Speed Mode does not work with OpenVPN Scramble, which is IPVanish’s obfuscation feature designed to disguise VPN traffic in restrictive network environments. If you need Scramble, you’ll have to turn off the DCO toggle. The two features can’t run together.
For most users in standard network environments, this won’t be a problem. But if you rely on Scramble to get past network restrictions, keep that limitation in mind before switching.
How to turn it on
Enabling High-Speed Mode takes about 30 seconds. Here’s the process:
- Open the latest version of the IPVanish Windows desktop app
- Click the Settings icon
- Go to the Protocol tab
- Select OpenVPN as your active protocol
- Toggle on High-Speed Mode (DCO)
No additional configuration is needed. If your app isn’t already on the latest version, update it first and the option will appear in Protocol settings.