Today we are going to discuss PTE depletion and Low Physical Memory conditions and how those two issues can lead to server hangs. In our post on the /3GB switch we mentioned that in general, a system should always have around 10,000 free System PTE’s. Although we normally see PTE depletion issues on systems using the /3GB switch, that does not necessarily mean that using the /3GB switch is going to cause issues – what we said was that the /3GB switch is intended to be used in very specific instances. Tuning the memory further by using the USERVA switch in conjunction with the /3GB switch can often stave off PTE depletion issues. The problem with PTE depletion is that there are no entries logged in the Event Viewer that indicate that there is a resource issue. This is where using Performance Monitor to determine whether a system is experiencing PTE depletion comes into play. However, Performance Monitor may not identify why PTE’s are being depleted. In instances where a process has a continually rising handle count that mirrors the rate of PTE depletion, it is fairly straightforward to identify the culprit. However, more often than not we have to turn to a complete dump file to analyze the problem.