Nvidia Optimus Support under XP - NVS3100mm vs Intel integrated

Question

Hi,
We are currently in the process of evaluating the T510 as our new standard laptop.
We are considdering purchasing teh 4314-9WG model, that has on board both the Nvidia Quadro NVS3100mm, as well as the integrated Intel graphics of the QM57 chipset. 
Now normally, the Nvidia Optimus system would enable the user to switch between these 2 graphics "cards"  on the fly (as I understand it). 
However, our current install image is still based on Windows XP SP3, as there is no driver support for Nvidia Optimus for XP.
Thus, we have the following question: 
Will our users be able to use the Intel integrated Graphics by default on XP, even though the Optimus witching will not work. 
or in other words: 
Is the Optimus driver a pre-requisite for using one or the other video card as default under Windows XP
What will the Laptop due without this driver? 
We would accept that for now, users would be bound to only use either the Intel integrated graphics, or the Nvidia Quadro. 

Answer 1

I am able to get the NVS3100 working ok under XP, except that is defaults to 16bit color for some reason, which I then have to change manually. 
Now, for the Integrated Intel HD Graphics, I do the following: 
In the BIOS, under Display, the "graphics device" is set to Integrated Graphics, and the "OS detection for NVIDIA Optimus" is set to disabled. 
I am using the latest drivers for Intel HD, 6.14.10.5313
When Windows XP boots, it detects 2 devices: 
- Audiodevice on bus for High Definition Audio
- Videocontroller (VGA Compatible)
If I now try to install the intel driver pack ( 6.14.10.5313 )  it will start with the installation for the Intel Turbo Boost Technology Driver. This seems to install without problem.
But when I click finish at teh end of it, nothing else happens. 
What I expect is that it would now start the install for the Intel HD Graphics setup. And it simply doesnt. 
If I first unpack the executable, i get a folder called DISPLAY6
Inside, I can start an executable called Setup (Intel HD Graphics Installer) But all this seems to do is start the Turbo Boost Technology driver setup again. And afterwards, again, nothing happens. 
I have tried it both from a situation where the NVIDIA drivers where previously not installed, and where they where installed and I switched it later. Both give the same results.
Its almost like it doesnt properly detect teh hardware, or cant see that the Intel driver goes with it. 
I have also tried to manually install teh driver, by pointing to unknown VGA device to teh unpacked driver location, but it doesnt find any drivers there that it can use.