CPU usage very high with Ubuntu 12.10

[Agresvig]

With the latest Ubuntu (12.10) I get CPU usage through the roof (20-60%) on host. In the guest, 'top' tells me that Compiz is the sinner, idling at 100-160% CPU, which I assume means that it is using over one and half core or something like that.

Host machine is a Core i7 laptop with 4 cores, 8GB RAM, Intel graphics (I have an nVidia achip but I believe its disabled), running Win 7 Enterprise 64-bit, with latest VirtualBox (4.2.2).
Guest is 32-bit Ubuntu 12.10, with latest "Guest Additions" installed. It's assigned 4GB RAM and all 4 Cores, no usage cap.

I've tried a bunch of different settings, but right now its running with the ICH9 chipset, IO APIC enabled, EFI disabled, PAE/NX enabled VT-x and nested paging enabled. 128MB video mem and right now both 2D and 3D accel is disabled, although I tried with both enabled, no difference.

I did install "CompizConfig" manager in the guest and disabled all desktop effects, same issue.

Anybody have the same issue? Any ideas what I can try?

Have you experienced this in earlier versions or is it likely a 12.10 introduced issue?

Thanks for all help.

[Agresvig]

It is likely related to the issues discussed in this thread: viewtopic.php?f=3&t=51727

Turns out Unity 2D is disabled in ubuntu 12.10, so 3D only, and 3D acceleration in VB 4.2.2 doesn't work in Ubunutu 12.10, we only get software rendering, therefore the high CPU usage.

I'll be using the Basic Gnome shell with no effects (boooring) until a fixed comes out for VB that makes 3D accelleration work again.

If anyone has a workaround I would love to hear it!