Microsoft's Delivery Optimization service, designed to accelerate Windows updates and Microsoft Store downloads through peer-to-peer sharing, has been causing significant system performance issues for Windows 11 users. The service, which runs as the Delivery Optimization Host process (DoSvc), has been documented to experience uncontrolled memory growth over time, consuming gigabytes of RAM and potentially leading to system slowdowns, application crashes, and instability. This persistent memory leak has frustrated users who rely on their systems for productivity and gaming, prompting Microsoft to investigate and deploy fixes through recent Windows updates.

Understanding Delivery Optimization and Its Purpose

Delivery Optimization is a background service integrated into Windows 10 and Windows 11 that enables devices to download updates and apps from other PCs on the local network or the internet, rather than solely from Microsoft's servers. This peer-to-peer approach can significantly reduce bandwidth usage for organizations and improve download speeds for users with slower internet connections. The service operates by creating a local cache of downloaded files that can be shared with other devices, theoretically creating a more efficient distribution network for Windows updates and Microsoft Store content.

According to Microsoft's official documentation, Delivery Optimization uses a combination of local network peers and internet peers (when enabled) to distribute content. Users can configure the service through Settings > Windows Update > Advanced Options > Delivery Optimization, where they can choose between downloading only from Microsoft servers, from local network devices, or from both local and internet devices. The service is enabled by default on most Windows installations, though enterprise environments often manage it through Group Policy.

The Memory Growth Problem: Symptoms and User Reports

Windows 11 users began reporting unusual memory consumption by the Delivery Optimization Host process (DoSvc.exe) throughout 2023 and into 2024. Unlike typical services that maintain a stable memory footprint, DoSvc was observed to gradually increase its RAM usage over time, sometimes reaching several gigabytes. This memory growth occurred regardless of whether the system was actively downloading updates or not, suggesting a fundamental issue with how the service manages its cache and internal data structures.

Affected users reported various symptoms:

  • Gradual system slowdowns as available RAM diminished
  • Increased disk activity as the system began paging memory to disk
  • Application crashes when memory became critically low
  • Task Manager showing DoSvc.exe consuming 2GB, 4GB, or even more RAM
  • System instability on devices with limited RAM (8GB or less)
Gamers and content creators were particularly affected, as their workflows demand substantial system resources. Many users initially suspected malware or other system issues before identifying Delivery Optimization as the culprit through process monitoring tools.

Microsoft's Response and Fix Development

Microsoft acknowledged the Delivery Optimization memory growth issue through various channels, including support forums and Windows Insider feedback. The company's engineering team identified the problem as related to how the service manages its internal cache and handles certain types of update metadata. Specifically, the issue appeared to stem from improper cleanup of temporary files and memory allocations after download operations completed.

Search results indicate that Microsoft addressed the problem through cumulative updates for Windows 11. The February 2024 cumulative update (KB5034765) and subsequent updates included fixes for memory management in the Delivery Optimization service. These updates implemented improved garbage collection routines and better cache management to prevent the uncontrolled memory growth that users had experienced.

Microsoft's official changelogs for these updates typically describe the fixes in general terms, such as \