VBox 4 - Random BSOD starting multiple VMs

[marco]

I'm starting to fear my decision to upgrade to rel 4, instead of waiting for a couple of "maintenances" as I've been usually doing, was not an happy one.
This morning, while attempting to start a second guest (which was in saved state), I had a BSOD, the first in a very long time.
Windows XP x64 host, many kind of guests.

I tried again, with other VMs, getting several other BSODs (0x..D1, DRIVER_IRQL_NOT_LESS_OR_EQUAL, pointing to the audio card driver), always during the start up of a VM, no matter if in saved state or not . There seems to be no link to a particular VM, even if actually the BSOD seems to occur more easily when one of the VMs is a Windows 7 guest.
All the VMs I'm using are "old" ones, which I've been using for a long time with no problems and which have not been recently modified in configuration.
For the first 5 or 6 BSODs, the VMs which were open lost their saved states (obviously) but could be normally started.
The last time, however, I was not even able to start one of them because of a corruption of the vdi file.

Luckily (or thanks to my caution) the VMs I used for these tests are not so important, as I use them for minor tasks. Loosing saved states or having to revert to some previous backups is quite annoying, but no more than that.
The fact is that now I fear opening the other VMs, before having this problem sorted out...

Nothing has been changed (installed or removed) from the host system.
Everything was working fine with my previous version of VBox.

One thing I noticed, which seems to me strange, is that the amount of used RAM reported from Task Manager did not correspond to the sum of the RAM assigned to the various VMs running. For example, during one of my tests, I was able to start a Win7 guest with 1280MB of assigned RAM despite only 600MB of RAM being available to the host system.

Thanks for any help

[stefan.becker]

Prosa doesnt help.

We need facts.

Exact descriptions.

Host: Hardware, OS, VBOX Version.

Running guests: guest configurations, os-versions.

From crashing guest: logfile, exact error messages etc.-

[marco]

Prosa doesn't help...

Well I'm humbly sorry then, I just tried to describe "facts".
Not reading carefully doesn't help either, I'm afraid.

...Host: Hardware, OS, VBOX Version.
Running guests: guest configurations, os-versions.

I wrote: "Windows XP x64 host, many kind of guests".
I also wrote the BSODs appeared after upgrading to VBox 4. Which means (clearly enough, I thought) I'm running Version 4.0.0.
As to hardware, I mentioned the audio card driver, the only one mentioned in the BSOD screen.
Anyway: Intel i7 870, 4MB ram, Asus P7P55D-E PRO Mother board, GeForce 9800 GT, exactly the same as before the upgrade.

From crashing guest: logfile, exact error messages etc.-

There is not a particular "crashing guest". The host system crashes, while VBox gets at roughly 3/4 of the way starting the second or third VM, no matter which one (Win7, WinXP, Debian, Ubuntu...) and no matter if recalling a saved stated or not.
No error messages whatsoever. If there had been any I would have posted...
I posted the error message from the BSOD, which leaves no trace in Windows' event viewer or log files.

I know very well that BSODs can "appear" to be caused by VBox but actually depend on some host system's weaknesses which VBox only makes more evident, but as I said this very same system has been working for a long time with VBox 3.x + VMs running (also together with other host applications) with no BSODs at all.
I could obviously post the log file of one of the many guests which where starting when the system crashes occurred, but I hoped to get some help and hints about that. I still hope, actually.
By the way, I re-started all the guests again after my many tests, finding out (as I already said) that one of them had the vdi file broken. Does this make the guests' log files useless for investigation?