VBox has Openbox-phobia?

[CAVT]

I decided to experiment with the lightweight versions of PCLOS, specially OpenBox and LXDE (which also uses OBox). Well, since I'm a bit reluctant to modify my partitions just to try, I went for VirtualBox, which I already sued for virtualizing succesfully WinXP. So I tried the following distros running from the ISO images in my HD, from burned CDs and then installing the distros in a virtual HD (I did so in order to compare performance):

-PCLOS 2010 KDE4/LXDE*
-PCLOS 2007 KDE3.5
-PCLOS 2009 LXDE
* I actually used the original and most common PCLOS 2010 ISO, the one featuring KDE4, and once I installed and upgraded it, I installed LXDE+OpenBox.

Well, I got weird and not very pleasant results: KDE was notably faster than LXDE! (yes, I put the same facial expression you, dear reader, are now putting, lol). So to see if this was an issue of PCLOS, I also tried for the sake of testing and comparisson other Mandy-based distros, which are sayed to be optimized for low-end hardware:

-Unity 2010 (Openbox)
-TinyMe 2010 (Openbox, based on Unity 2009)
-TinyMe 2008 (Openbox, based on PCLOS 2007)

Now, I configured the virtual machine in the following way: a dynamic 20GB virtual disk, 256MB of RAM out of which 32MB were destined for video (I did so in order to compare better how resource intensive is each distro), and tried configuring the system type both for Linux Kernel 2.6 and Mandriva Linux (one at a time, naturally). My "real" machine is a Sempron Le-1100 with 2GB RAM, Biostar mobo with NVIDIA chipset (GeForce 6200 256MB onboard) and proudly running PCLOS 2009 KDE3.5.

Running the distros from an actual live CD in the normal non-virtual way exhibit no kind of issues in any case, all of them performed as expected and flawlessly. Now, when going virtual... all the distros that used OBox although mantaining a relatively low ram consumption (generally under 150MB inside the guest when most exiged), had a very high CPU usage, rarely going below 50% and easily reaching 100%. To put it plainly, it felt like using Win Vista in an old computer, sometimes the mouse would have an intermitent choppy behaviour. TinyMe 2008 was the only one that had a smoother response.
PCLOS 2010 KDE felt slow, but that was logical and perfectly expectable (I had to increase the VM ram availability to 764MB, otherwise booting was ethernal). When installing LXDE the situation improved and could go for 256MB or even less (I risk it could run fairly in a 128MB machine), but with the CPU usage problem. PCLOS 2009 LXDE was no better, and PCLOS 2007 KDE3.5 can be considered the winner, as it was at least as smooth as TinyMe 2008 given that PCLOS 2007 is much more resource intensive than TinyMe. In general the KDE distros had a higher RAM usage but lower CPU exigences.
Lastly, I used first VBox 2.2.4 and then Vbox 3.1.8, but it dind't make any difference.

Does anybody have any clue of why could this happen? It's strange, because for example, when I use KDE+Obox I do notice an increase in performace in my everyday system compared to KDE+KWin.

[menotu]

Without going into too much detail, I would think you would have to test each VM from a fresh reboot of your main desktop system, as testing one after the other will get slower and slower........

No matter what your system may be telling you, memory is never fully released until a reboot or back from hibernation (in fact using hibernation is a good way of refreshing your memory - a bit like a humans sleep  )

Secondly. PCLinuxOS isn't based on Mandriva

[CAVT]

Mmm, there seems to be some change, but not like I expected. I tried with PCLOS 2009 LXDE and after short time pages like YouTube become sluggish, even if the video is fully loaded, but anyways, it's not a memory problem, it's the CPU which is exiged, the RAM usage remains pretty free and there's no swap usage (my swappiness is 5), so must be that OBox is not suitable for virtualizing or VBox doesn't do a good job with OBox. I'll keep trying with the rest.

[CAVT]

Ok, rebooting doesn't solve much the problem it seems. However, I did one test, I had previously downloaded OBox, E17 and BlackBox once upon a time to see if how they were. Well, OpenBox was using less RAM than KDE+KWin, but the CPU usage was fluctuating, while E17 and BlackBox showed a more stable behaviour, and certainly lighter than KDE. So I suppose it must be an issue of my CPU not handling properly OBox instructions. Of course that it wasn't extreme like when virtualizing, but maybe that condition simply increased the effect... it's my speculation based on what I saw, but I don't have the knowledge to test it more thoroughly.