Removing HyperThreading - But Windows won't recognize it.

[cpuphantom]

Hello.

I just purchased a new server with a single Xeon Processor with HyperThreading. HyperThreading came enabled from the vendor and Windows Server 2003 was pre-installed. The HAL is set as an ACPI Multiprocessor HAL.

The software I'm installing on this server is a call processing software, and the vendor of that software told me to get HyperThreading off the machine. It would cause performance issues with the calls, and boy has it.

So I disabled HyperThreading in the BIOS. But Task Manager still shows two separate processor graphs, and the HAL still shows ACPI Multiprocessor.

I understand that I should update the HAL as well, but can't find any information that says its possbile to go back from Multiprocessor short of reinstalling the entire server operating system.

So does anyone know a way to make Windows 2003 only use the processor as a single processor without reinstalling? Or is Reinstalling the only way? I can update the Driver for the HAL, but my only non-multiprocessor option is "Standard PC" and I'm not familiar with it. Will that do the trick?

Thanks so much!

 

[skialta]

That just doesn't sound quite right. Win2003 should automatically update unlike NT 4 where you did have to do some tricks to go from a single processor to dual. If your phone vendor is anything like the various vendors I've dealt with including phone and security, they don't know computers at all. Typically they say exactly what the manual says and that's it. To give you an example, at my company we have a new security 'server' that the vendor insisted had to run WinXP Pro...actually they wanted Win2000 Pro, but we went with XP. So I ended up loading WinXP Pro on a PowerEdge server...BTW, I should mention that the vendor also told us we should install SP4 on that XP machine and we should have the full version of MSFT SQL 2000 installed. Anyone that is familiar with computers knows that you cannot install MSFT SQL 2000 Server on a desktop OS (except the developer edition or MSDE). Just my $.02. My suggestion is to do some more research and don't assume that the vendor actually knows what they're talking about.

 

[cpuphantom]

heh heh, you are right about the vendor not knowing computers.

But here's what I know... according to what limited part of the MCSA I have studied so far, Window XP (at least) may actually require you to manually update the HAL in the Device Manager from ACPI Uniprocessor to ACPI Multiprocessor if you add a second processor after installing XP with a single processor. I'd imagine 2003 is similar.

My research online shows the same. I've found plenty of info (from the MS Knowledgebank) about using Device Manager to update the Uniprocessor to Multiprocessor. I just find almost nothing about taking it from Multiprocessor back to Uniprocessor. Apparently not a lot of people remove processors, heh heh. I also find nothing really regarding turning off Multithreading.

So... before I go and reformat and reinstall Windows 2000, and the Call Attendant software with it, I thought I'd ask the experts and see if anyone knew how to step it back short of a reinstall.

Oh yeah, can't remember if I mentioned this before but I also ran the Repair option from the Install disk and it still didn't step back the Multiprocessor HAL.

 

[PScottC]

It sounds like a HW problem to me. I disabled hyperthreading on a HP DL380 server and the second CPU graph went away for me. It did leave behind the ACPI mulitprocessor HAL though. Verify that you have the latest and greatest BIOS firmware from your server vendor, then verify that hyperthreading is off in the BIOS.

One more thing.... I'm sure you checked this, but is there actually only one CPU in the system? Remember hyperthreading doubles the number of servers shown in Task Manager. (2 CPUs show as 4, 4 as 8)


PSC

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