FSCTL_IS_VOLUME_MOUNTED repeated for 5secs ?!?

[quantass]

We're using Rainbow Portal .NET v1.5 as our CMS to compose many of our
sites. We develop several .ASCX controls and Rainbow easily plops them
onto a dynamically created page. I've been asked to look into why a
paritcular area of our site is running slowly as compared to other
areas. I discovered several blotttlenecks and have resolved them to
the best I could but one remains.

When i hit the page there is normally a 5 sec delay before the IE
browser displays the site. On subsequent refreshes it takes about 1
sec. Clearly ASP.NET has cached what it needs. I then wait for about
2 mins and do a refresh again within the IE browser. Now the page
takes about 5 secs or so to display. I dont get it. I thought .NET
already had the page cached?

I then launched FILEMON to investigate all the IO file access by
ASPNET_WP.exe and INETINFO.exe. Several Rainbow files (theme, layouts,
dlls) are accessed but these consume less than 1 sec. The majority of
the time was spent here:

1:35:11 PM sqlservr.exe:688 WRITE C:\Program Files\Microsoft
SQL Server\MSSQL\Data\Rainbow_log.ldf SUCCESS Offset: 7912448
Length: 512
1:35:13 PM aspnet_wp.exe:2488 OPEN
C:\winnt\microsoft.net\framework\v1.1.4322\tempora ry asp.net
files\root\061162b5\7a6ac1c\assembly\dl2\c9b3b93f\ b2d1d96e_8893c501\solpartwebcontrols.dll
SUCCESS Options: Open Access: All
1:35:15 PM inetinfo.exe:1140 OPEN
C:\PROJECTS\RAINBOW\DESIGN\THEMES\NEWCOUNTYSITE\DE FAULT.CSS SUCCESS
Options: Open Access: All

You can see a time of 4 secs was consumed. I discovered an Advanced
mode of Filemon and it revleaed:
aspnet_wp.exe:2488 FSCTL_IS_VOLUME_MOUNTED C:\WINNT\system32
SUCCESS

This line is repeated several times before and after the .DLL and is
consuming the majority of the time. On refresh of the page, it does
not exist whatsoever. Any ideas?