Severe FritzOS bug slows down speed sometimes drastically

The new FritzBox models with Wi-Fi 7 were actually supposed to set records. But updates to FritzOS 8.2x may now slow down two top models, sometimes dramatically. There is at least an interim solution for affected users.

FritzOS 8.2x slows down high-end routers

FritzOS 8.2 is currently being distributed to FritzBox routers in various stable versions and laboratory variants. Anyone who is currently the proud owner of one FritzBox 5690 Pro or FritzBox 7690 However, you may experience a nasty surprise after installing an appropriate update. According to user reports, instead of the expected high-end performance, the speed sometimes drops noticeably.

The problem primarily affects users who do not operate their router directly on the connection, but via an external modem on the WAN or LAN port. Despite correct synchronization, the effective data rate sometimes drops from one gigabit to less than 100 Mbit/s. Players also report unstable ping times, which makes online games a game of chance.

Hardware acceleration issues

The technical cause lies in a function that should actually have the opposite effect. The so-called hardware acceleration actually relieves the load on the router’s main processor. Specialized circuits handle the routing of data packets at Layer 2 or Layer 3 level without the central processing unit having to inspect each packet individually. However, with the current FritzOS 8.2x versions there seems to be a serious conflict between the operating system and the new chipsets of the Wi-Fi 7 generation, which blocks precisely this efficient data flow.

Help via hidden support menu

The good news is that full speed can be restored. Like the attentive colleagues from Deskmodder report, the incorrect packet processing can be switched off manually. To do this, users have to call up the FritzBox’s actually hidden support page, which is not linked in the normal menu tree of the user interface. It can be accessed in the browser at http://fritz.box/support.lua. There you will find the option to deactivate hardware acceleration at the bottom.

As soon as this function is switched off, the CPU takes full control of the data traffic again. The so-called software routing is more computationally intensive, but it bypasses the error in the acceleration logic and immediately cancels the artificial throttling. However, this coin has a downside. Because the deactivation is probably not permanent. Since hardware acceleration is essential for energy efficiency, FritzOS automatically reactivates the function every time the router is restarted.

Then the interim solution must be applied again. The affected models are among Fritz’s most expensive. The FritzBox 5690 Pro often costs over 300 euros in stores and is aimed at enthusiasts who expect uncompromising performance. The fact that the premium devices of all things are now struggling with firmware problems that massively affect performance is causing owners to be dissatisfied.

Fritz is still silent

Even if there is no official information about this yet, it is to be hoped that Fritz is already working on a solution that will be rolled out as part of an upcoming laboratory version. Until then, affected owners of a FritzBox 5690 Pro and 7690 can only resort to the bag of tricks of hidden router settings.