Your computer could only be pulling one-third of your promised internet speeds, and it wouldn’t even be the ISP’s fault. Certain Windows settings can hog bandwidth, and you can try changing them. To further improve the connection, you can switch your DNS resolver to Cloudflare or Quad9, which promise a more stable and secure connection.

However, you’ll reach a point where these factors matter little, and the biggest variable affecting performance will be how your network adapter communicates with the CPU. Even though this is rare on modern PCs, relying on the legacy line-based interrupt method means missing out on significant performance gains.

Legacy interrupts vs. MSI mode, explained

Your network adapter’s interrupt mode impacts latency by more than you think

Credit: Amir Bohlooli / MUO

All onboard devices send their requests to the CPU before Windows can process them. The messages are sent as interrupts to the CPU, and each device has a specific IRQ number to distinguish it. They’re sent along physical interrupt lines to the CPU and grouped together, which can cause small amounts of latency because the CPU has to sort each request before processing it.

For a network adapter, this can significantly impact your latency and ping in online games.

MSI mode cuts down this communication gap by mapping a special memory address from your device directly to the CPU. Then, your CPU doesn’t have to sort the request from the IRQ lines — it can process it directly, reducing latency and improving communication.

Find your adapter’s current interrupt mode

A quick trip through the Registry Editor

Most of the time, your network adapter is already in MSI mode, but it’s still important to check. To do so, first head into Device Manager and find your network adapter under Network Adapters. From there, choose Properties -> Details -> Property -> Device Instance Path and copy it.

Now, open Registry Editor and follow these steps:

1. Enter this path: HKEY_LOCAL_MACHINESYSTEMCurrentControlSetEnumPCI.
2. Now, add the Device Instance Path copied earlier and paste it next to this address.
3. Now, head into Device Parameters -> Interrupt Management -> MessageSignaledInterruptProperties.
4. Find MSISupported and check the value data. Change the value to 1 to enable it.

Even if MSI mode is active, you still won’t get full performance from your network adapter because interrupt priority matters in how your CPU sorts requests, even for message-based interrupts.

How to change your interrupt priority

MSI Utility v3 fixes the long process

Credit: Shaheer Khan/MUO

Even though MSI mode alone vastly improves performance over line-based interrupts, the CPU still needs to be configured in order to respond quickly to interrupts. There’s a very convenient way to do so via MSI Utility v3, a small Windows tool that can adjust the message-based interrupt priority.

Simply download the tool and open it as administrator to allow it to make registry changes. You may see several devices connected via PCI, such as your GPU, USB devices, and more, but you only need to configure your network adapter. Under interrupt priority, change it from undefined to high and close the application.

Testing real-world performance impact

The reduced latency shows the real win

My network adapter was already in MSI mode, so I knew I wasn’t missing much performance compared to legacy line-based interrupts. Nevertheless, I was inclined to see the difference in interrupt priority, so I ran a latency test first, then a couple of online titles to see it.

Aside from testing these latency spikes under load, I also ran a couple of multiplayer games to see how big of an impact I’d notice in-game, where the difference is actually supposed to matter the most.

Changing the interrupt priority to the highest didn’t magically increase my internet speeds, nor did it reduce the lowest latency I was getting, but it made my connection more stable, as evidenced by the maximum latency in the latency test above. In the gaming test, packet loss improved significantly, so I became more accurate and missed fewer shots.

Won’t fix a bad ISP, but will smooth an already decent connection

Now, don’t expect an increase in download speeds, because changing interrupt priority only fixes the problem locally and has no impact on your connection speed from the ISP. Sure, you’ll get a much more stable connection and improved ping in online games, but if your internet is inherently terrible, then changing interrupt priority might not do much for you. In rare cases, where it may cause problems and worsen the connection, you can always revert the priority to undefined.