My DC++ lags or the CPU usage is too high. What can I do?

Created by eMTee on on 2009-06-22
lag 100 cpu
Last updated by:
eMTee on on 2012-09-27

If DC++ constantly produces high CPU usage, lags for some time or freezes, please read the following before reporting it as a bug. You must understand that in almost all cases,this kind of problems are not related to DC++ directly. Going through the following steps you will most probably find a solution for your problem.

1. DC++ does NOT need much hardware resources in general but of course it won't perform too well on a very old computer. The minimum hardware requirements for normal user experience as follows :
- 512MiB of system memory (1Gb recommended) for Windows XP.
- For Vista and onwards you need at least 1,5GiB memory - the more the better.
- 1GHz or faster CPU
- UDMA compatible PATA or any kind of SATA hard disk (if its overall size is bigger than 20GiB, then it is new enough to meet this criteria)
- Chipset, storage, network and video drivers properly installed
Make sure your computer meet this minimum criteria.

2. Make sure you are using the latest version of DC++. If you use the latest >stable< version then check the official DC++ home page if there is an even newer unstable (test) release available. If so then upgrade manually to the very latest version marked as >unstable< to see if it solves your problem. The official DC++ home page is :

3. Try to reduce the number hubs (or rather the overall usercount) you're logged in at the same time. Less than 50000 users overall is what can be considered the normal usage of DC++. If you're above that number then you probably found the reason of your performance issues. If you're on large number of hubs then try to pinpoint the problematic ones by closing them one by one - a malicious hub can cause performance drops as well as it can use your client to attack others.

4. Many software can be incompatible with DC++ especially system; security/protecting (anti-virus, anti-malware, firewalls) and file system indexing software (media indexers, desktop searching software, etc..) can fall into this category. Any software which constantly monitors disk and/or network activity can be suspicious. In the majority of cases the high CPU usage problem exists because of a low quality or outdated third party software. Another possibility is that exceptions are not properly set for DC++ or they're outdated in the settings of security applications you use. This can easily happen when you upgrade DC++, read this FAQ for more information :
Most of the security software usually run as a service; they hook themselves into standard system calls which ordinary applications (like DC++) use. This results that the additional CPU usage of these software are added to the CPU usage of DC++ and this additional CPU usage is shown for the DC++ process in the Windows Task Manager. This often leads to the false conclusion that DC++ is what keeps your CPU busy.
If you use kind of these monitoring software, make sure you use the very latest version of them. Try to disable or better >uninstall< them temporarily for a test (for most of these security software, you can fully disable their effect only with uninstall only, even if they claim that their functions are disabled).

5. High CPU usage problems is often caused by hardware or driver problems.
- Make sure you have the latest available drivers installed from your (OEM) hardware vendors (focus to the chipset/system, storage and networking drivers as these are the source of driver related lags or freezes in almost all cases).
- Do some basic memory and hard disk tests to ensure that they are 100% error free. In Windows Vista and newer you find memory testing possibility in the boot menu (keep pressing F8 at boot to get the menu). For Win XP or older operating systems the recommended memory testing software is Memtest86+ ( ). For both test programs, run several passes to be sure your memory modules are fully healthy.

6. If your problem still exists and you think you found a bug in DC++ then follow this FAQ to know how to make an useful report for problems like freezes or high/100% CPU usage :