Disk optimization

flexVDI supports two types of virtual disk drives: ide and virtio.
The guest creation wizard defaults to ide disks for windows guests, because virtio drivers are not included in windows installers, and standard windows installation on virtio drives will fail. But disk performance is improved using the virtio driver. Linux, FreeBSD, and other OS installers include virtio drivers, and can be installed as virtio from the begining without any specific action.

Once a windows guest machine has been installed with ide disks, you can upgrade it to the faster virtio performing the following steps:

Create a virtio disk

You need to create a temporary disk image of type virtio. In this way, the virtio driver will be actually installed.

Install the virtio driver

Modify the virtual machine to use only virtio disks

Start the guest again

And that is all. The guest will use virtio disks and you will experience the improved performance.

General guest optimization

In order to optimize the performance of your guests, you can tune the configuration of your guest OS:

You can find more general advice on optimizing guests, and also windows guest optimization tools searching for "optimize your_os_version_goes_here guest performance".

MS Resource Monitor is a good tool to study and optimice the guests resource usage (CPU, disk, network) specially before converting them to flexVDI templates.