Hyperthreading YES/NO ?

Today i have a dual 3.6Ghz P4 with 3 gigs of ram with Hyperthreading turned on for the Orion poller. This system has Orion, as well as the Wireless and Application Monitor plug-ins. Running windows 2003 Enterprise. Our SQL server is running dual dual-core 2.8Ghz with 6 gigs of ram and it too is running with Hyperthreading on. Its OS is 2003 Enterprise X64 and the SQL server is also Enterprise X64.

My real question is, should i have hyperthreading enabled within Bios. From what I see, no single process can use more that 50% of a single CPU / Core which is bad if you ask me.

Also if the recommendation is to disable hyperthreading, since I have dual physical CPUs in each system do I have to worry about the OS puking after turning it off?

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mark_wiggans

You may leave hyperthreading on. The remark about 50% utilization is a misnomer due to how MSFT reports utilization in a dual core or hyperthreaded environment
It is my understanding that if you have 4 processors, real or virtual, any one process will show a max fo 25% CPU utilization which in effect means it is maxing one of the 4 CPUs.

jkeberle

mark, I understand what you are saying, but when i first boot up the Orion server which is dual CPU's running HT, and i bring up the task manager, it shows me 4 CPU graphs. Also when i monitor the applications for CPU usage NetPerfmonService.exe is sitting at a solid 25. which according to you states that its using 100% of one of the 4 CPU's. the only issue is that there are only 2 REAL cpus in the unit and they are not dual core.