Rawdisk access Linux guest is slow on Dual Boot

[MCFurry]

I have the following setup:
- Host OS is Win10 with a dualboot installation with Ubuntu precise (12.04 64 bit)
- Virtualbox Guest is the Ubuntu partition via rawdisk access.

Launching the Ubuntu partition within virtualbox works fine, performance is pretty good! However, whenever I actually dualboot to the Ubuntu partition itself, performance is pretty bad. Intense tasks like code compiling for example goes very slowly compared to the situation before I ever accessed the partition via rawdisk access. Also graphics performance seems to be quite bad. I.e. video playback or dragging windows. In fact, I sometimes feel that the performance inside virtualbox is much better then when actually booting the Ubuntu partition itself.

What could be the problem here? Is it maybe that the virtualbox guest additions are also started during a regular boot and influence performance? And if so, how do I make sure they only launch within a virtualbox session?

Hopefully I made my problem clear and someone has some suggestions?

[mpack]

Disks are emulated hardware, so Guest Additions have no bearing on disk performance. Why not just pop up the Ubuntu equivalent of the task list and see what's using the CPU or I/O time? And you should probably ask about this on an Ubuntu support site, since VirtualBox isn't involved.

[MCFurry]

Thanks for your reply mpack. I did a quick check on the process list en disk usage but could not find anything strange. However I disagree with the fact that VirtualBox isn't involved. The Ubuntu installation has worked great before, but ever since I made it available on Windows as a virtualbox guest by using rawdisk access, the installation has become slow. But only when actually booting to Ubuntu, in VirtualBox it still seems okay. That's way I was thinking that maybe during a regular boot to Ubuntu the guest additions are also loaded and conflict with the actual hardware?

[mpack]

If VirtualBox isn't running then it can't be involved.

[MCFurry]

And what about the VirtualBox GuestAdditions? Those are installed to the Ubuntu part as well. Do they detect a regular or virtualbox boot?

[mpack]

You haven't provided any evidence that the official GAs are even running, so estimating their effect is premature. We already established that the GAs are irrelevant to disk performance. They are involved with graphics, keyboard and mouse, GA shared folders, copy & paste. That is if you are using the official GAs. If you are using the Ubuntu fork GAs then you need to ask about them on an Ubuntu forum.