Question : SQL Server - CPU "Flatline" Problem

I have tried everything I know to pin down this problem, and I am stumped.  Hoping someone, somewhere, has seen this before and can tell me the ABC's for resolving it.

Environment:
     SQL Server 1 - appmonroe2o6aa - SQL 2000, Win 2003
     SQL Server 2 - appmonroe2o6ac - SQL 2000, Win 2003

About a year ago, we began to experience a problem with server 2 where -- at seemingly random intervals -- the server CPU usage will "flatline" at just about 12 percent (see attached screenshot).  When looking at Task Manager on that server, the 12 percent is almost entirely consumed by the SQL service.  Even though the CPU is only 12 percent taxed, SQL Server performance grinds to a near halt.  Every transaction takes magnitudes longer than normal, and there are widespread "timeout" errors and "recv()" errors throughout all systems that access the server (mostly web apps, hosted by our Win 2003 IIS server).

To resolve the problem, the only solution I have identified is to restart the MSSQLSERVER service.  While this resolves the problem temporarily, it still pops back up -- again, without any apparent causation -- several times a day.  And of course while the service is restarting, EVERYTHING is down, which is very disruptive to the users.

We even brought in a "SQL Server expert" at one point to help track this down.  His suggestion was to run a trace on the server and try to make a correlation between what transactions occur just before the flatline problem.  I did this diligently for several months, and every time I thought I saw an anomaly, I made changes to prevent that type of transaction, but the problem never went away.  The other problem was, if I didn't sit and watch the CPU usage constantly, I could never know the exact time that the flatline began, so even reviewing trace logs was like finding a needle in a haystack.  To date, I have not found any evidence of a direct cause whatsoever.

This problem has NEVER occurred on server 1.  It only occurs on server 2 (which, ironically, is newer and about 4x more powerful than server 1).

Please -- does anyone have suggestions?  It is getting really frustrating to babysit this server all day every day.

Answer : SQL Server - CPU "Flatline" Problem

yes, my screenshots are for sql 2005.

> I don't see an analog to the "max degree of parallelism" setting --
that would be the "parallelism" section of the CPU tab, you have set "use all available processors".
change that to "use 1 processor"
-> needs restart of sql server

in the memory tab, change the max memory from 8191 to 7700 for example.
-> does not need a restart of sql server.