What Virtuozzo Means By "isolated"

I'm using a brand new Virtuozzo VPS, with (512mb) SLM memory managment, that standing to some "experts" would be a great way to manage memory, a great virtualization solution, and such.

This VE, supposedly, is hosted on excellent hardware (sas-scsi raid i/o, etc), so should have great performances, especially considering i don't run any control panel, i just run apache2+mysql5 (no email system or else), and i manage everything by myself (and i'm really experienced).

I'm experiencing on the contrary much worse performances than my previous 256mb XEN vps.

Sometimes you hear (virtuozzo fanboys i guess) about XEN slowness problems instead, because xen - supposedly - hasn't got a proper disk/io scheduler BUT provides individual custom swap space, so a customer could create a 5GB swap space and disrupt host machine performances by clogging the VPS, swapping a lot, causing insane i/o wait, etc... I've read a lot of topics about this "debate" in the past.

So you would expekt Virtuozzo having a wonderful cpu and disk i/o scheduler, instead.

You can read on Virtuozzo Website the following Claim : "Complete Isolation - VEs are secure and have full functional, fault and performance isolation."

On the contrary i'm having a lot of issues, supposedly coming from "bad neighbours", like idiots not being able to handle security of their vps, spammers, and so on, on my new virtuozzo VE ...

Everytime someone crashes his own VE on the same host machine, like causing a 100.0 load, even my VE goes offline with 400% i/o wait ...

My hosting provider (which i won't name at all, anyway) is doing an excellent job trying to minimize my inconveniences, really: but - in general - i'm beginning to wonder wheter this insane behaviour is "common" for a virtuozzo solution.

In short, I'm wondering - and i'd like an expert opinion on this - HOW THE HECK could this be possible ??

Isn't Virtuozzo supposed to have a I/O and CPU scheduler ? How in the earth can a single abuser loading insanely his VE affect all the other customers VEs ?

Can a host-server running Virtuozzo, be monopolized (100%cpu and insane i/o wait) by a single abusing VE ?

If this is true, i really don't understand where Virtuozzo advantage would be. Neither i understand the "complete performance isolation" claim by SwSoft.