Advice needed to set RAM size for XP guest

[simbeb]

Hi

I installed Virtualbox on my main PC which is a laptop with an AMD Turion dual core 2ghz, 4gb RAM, running Windows 7 Pro. My guest OS is XP on a 10gb expanding virtual drive. I set the RAM for the guest OS as 768mb and I find my virtual XP extremely slow to respond to even installing software or opening a folder. Is the RAM I allocated to it too low or is the problem elsewhere?

Cheers

[dmcgraw]

I don't know about the slowness, I would think 768 MB would be enough for XP.

But why did you set your drive to 10 GB? I suspect you will quickly run out of disk space.

[MarkCranness]

768MB is fine.
Have you installed the Guest Additions (see section 4 of the user manual).
Some people report that the host CPU usage is high, even when the guest is idle. What does Windows Task Manager (on the host and on the guest) say about CPU usage?

[mpack]

It's also worth looking in the process list in task manager to see what junk is running. Resident antivirus apps in particular can waste a lot of CPU.

A basic XP install runs fine in 256MB. 512MB is the sweet spot IMHO.

[simbeb]

Hi

It's an expanding drive so I can't run out of space.

Yes I have installed the guest additions

The cpu usage of the host goes up to 50-60% without anything much going on on the guest, and cpu usage on the guest goes high too: peaks over 35% sometimes. I don't quite understand...

It's a very basic XP install with no 'junk'. I have installed a basic AVG antivirus and Zonealarm firewall and they are the only apps running at startup along with the VGXtray from Virtualbox (is that really needed?)

[SecretCode]

I run XP guests at 512MB with no problem - this keeps more memory available to the host. If I was running a lot in the guests I suspect I might need to increase to 768MB.

It's an expanding drive so I can't run out of space.

Even dynamic disks have a fixed maximum size. How big does the guest say the drive is? You will run out of space when you've used that much. Then you have to increase the vdi size in the host, e.g. using clonevdi. This takes time.

[MarkCranness]

The cpu usage of the host goes up to 50-60% without anything much going on on the guest, and cpu usage on the guest goes high too: peaks over 35% sometimes. I don't quite understand...

If CPU usage on the host tends to stay at ~50% on the host even when the guest is idle, you may have one of the CPU usage problems.

If high host CPU usage only starts after a while, and is perhaps triggered by the guest using the internet, then try disabling the guest firewall (a fix for this problem will be in the next version).

If high host CPU usage is present right from VM boot, then try using HALu to change the guest XP HAL, and change it to 'Advanced Configuration and Power Interface (ACPI) PC'.

My own experience (and others) is that VirtualBox does not handle SMP (Multiprocessor) VMs well: Often the host CPU goes to 100% for no reason, even when the guest is idle.

These HALs require IO APIC enabled and may have host CPU usage problems:
ACPI Multiprocessor PC (HALu=ACPI Multiproccesor PC)
ACPI Uniprocessor PC (HALu=ACPI Uniproccesor PC)

This HAL doesn't care about IO APIC and will not have host CPU usage problems:
Advanced Configuration and Power Interface (ACPI) PC (HALu=ACPI PC)

If changing the HAL works for you, then please add your details to this bug ticket: Huge IO-APIC/guest SMP overhead with 32 bits guests (you will need to register a new account: Use the 'Register' link at the top-right of the bug ticket page.)

[simbeb]

I am probably not enough of a geek to have understood everything that is explained in the latest post, but thank you for trying to help me anyway I will look more into it if what I've done over the weekend has no effect:

I have wiped the 25gb XP partition on my computer (I was dual booting XP and Win7),created a 20gb virtual drive, put it in that partition and re-installed XP on it. Hopefully, the increased space and dedicated partition should help...

cheers,

fred