This article was previously published under Q191098
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A large file copy operation causes available bytes to drop significantly.This happens when a Windows client copies a large file from or to a WindowsNT computer.
In this case, you will notice a user interface performance degradation. Thefiles need to be about the size of the physical memory of the computer orgreater.
If you look at performance counters while this happens, you find that thecounter for the file cache (Memory: Cache Bytes) goes up while the processworking sets (Process: Working Set, instance _Total) decline. Availablebytes (Memory: Available Bytes) declines in the inverse proportion of thecache bytes.
While copying the files, Windows clients do not use the flagFILE_FLAG_SEQUENTIAL_SCAN to open the files. Thus, Cache Manager tries tocache the whole file in memory and causes the file cache to grow and, thus,available bytes to drop.
To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
152734 How to Obtain the Latest Windows NT 4.0 Service Pack
Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.