Number of supported cores?

[EveryoneLovesMe]

Call me inept, but I can't seem to find any information regarding the number of cores supported in VMware Workstation 6. I am using an Dell Optiplex 755 with a quad core processor and Windows XP SP2. I know that Windows XP has a 2 processor/core limit, but is VMware Workstation able to use more cores and RAM than officially supported under XP 32-bit as the host? Would some flavor of Vista work better in this situation to allow access to more cores and RAM?

AM

[EveryoneLovesMe]

This one must be tougher than I thought. Now I don't feel so bad!

AM

[asatoran]

Yeah, I thought it was an easy answer, but the only info I can find is references to saying the host can have "multiple cores." While Workstation might be limited, I thought I read on the forums that Server can use as much as the host has, at least 4 cores anyway. (Correct me if I'm wrong.) So I'd guess that WS6 is at least 2 and possibly 4 cores and Server is at least 4 cores. And ESX I think can handle more cores.

[louyo]

I am running WS6 on a Quad Core with OpenSUSE 10.3 host with no problems. Performance is great.

I only assign one processor to VM's.

Lou

[admin]

I think it's a question of what you mean by "number of cores supported" - do you mean the number that the host has, or the number that a guest can make use of? At least for Fusion, guests can use 1 or 2 cores, but Fusion itself can use more (useful only if you run multiple VMs). So if you have an octo-core machine, you could run three 2-processor guests running at full blast and have some left over for the host. I think Workstation is similar, though I'm not sure.

As a hosted product, I would expect Workstation to be limited to whatever the host gives it; e.g. even though Workstation would run on a quad-core machine, if Windows only schedules two cores, Workstation will be limited to 2. Similarly for RAM - I think 32-bit Windows has a 3 GB limit, so in this configuration Workstation will be limited to that.

Disclaimer: I'm not a Workstation expert, and rarely use it.

[asatoran]

EveryoneLovesMe wrote: ...but is VMware Workstation able to use more cores and RAM than officially supported under XP 32-bit as the host? Would some flavor of Vista work better in this situation to allow access to more cores and RAM?

Of course, we assume that the host OS can handle all the cores/processors that the host hardware actually has. If the host OS only works with 2 cores, then this is a waste for your quad-core machine.

As a hosted product, I would expect Workstation to be limited to whatever the host gives it; e.g. even though Workstation would run on a quad-core machine, if Windows only schedules two cores, Workstation will be limited to 2.

My answer to the OP was on this interpretation; how many cores/processors can the host use to serve VMs. Server1 documentation says it can support up to 16 x86 processors on the host. But WS documentation only states "Multiprocessor systems supported." But is that 2, 4 or 8 processors?

[louyo]

Using Ksysguard to monitor cores, it appears as though all of them are operational for multi VM's using WS 6.0. I am running 64bit OpenSUSE.

Lou

[Scissor · Accepted solution]

I highly doubt that VMware will magically find processors or RAM that are not recognized by the underlying OS (Operating System).

Micrsoft differentiates between physical and logical processors. Physical processors take up a slot on your motherboard. A single physical processor can have one or more logical processors (cores).

For Windows XP, according to , "Windows XP Professional can support up to two processors regardless of the number of cores on the processor. Microsoft Windows XP Home supports one processor."

For Windows Vista, according to , Vista Business, Enterprise, and Ultimate support 2 physical processors while the rest only support 1 physical processor. None of the Vista versions are limited in the number of processor cores supported on each physical processor.

However, since you only have a single quad-core processor installed, any modern version of Windows will support all four of your cores. Bring up Task Manager in Windows and you should see all four of your cores listed under the Performance tab.

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You asked if you should consider installing a 64-bit version of Windows XP/Vista. My opinion is that most people should stick with a 32-bit version of Windows unless:

• You have a 64-bit processor (of course)...

• and... You have more than 3 GB of RAM installed on your HOST and your current installation of Windows does not recognize all of your RAM.(32-bit Windows can address up to 4 GB RAM, but some motherboard/chipset/video card combinations can reduce the addressable limit down to 3.2 GB (or less) under 32-bit Windows installations).

• or... You have some software you want to install on your host that requires a 64-bit OS.

Hope this helps answer your question.

[EveryoneLovesMe]

Thanks for the effort, and this should answer the question. I'll update if my setup differs from these comments.

AM

[Scissor]

I think I might be mistaken on one point in my previous post. Based upon some more googling tonight, it appears that if your host has a compatible 64-bit processor, then you might be able to run a 64-bit Guest regardless if your Host OS is 32- or 64-bit.

It looks like there is a Processor Check utility that you can download to check and see if your 64-bit Processor has the necessary features required to handle running 64-bit Guests at all: .

Someone else will need to verify my above assumption as my laptop processor fails the Check utility and therefore can't be used to validate this claim.

I will edit my above post to correct this oversight.

[MtMan]

Yes indeed you can run 64 bit guests with a 32 bit host OS. I have WS 6 hosted on Windows XP (32 bit) and I run 64 bit linux distros.

You are limited by the amount of memory made available by the host OS however, but WS is a great environment for development and test.

[kdshapiro]

You can use a 64 bit guest under a 32 bit OS if your processor supports the VT bit. Low end dual core 64 bit processors such as the T5250 do not support the VT bit.