Android :: Importing Contacts To The Device - Contacts Operations Are Very Slow

I have some questions concerning importing contacts to the device, which is extremely slow.

First of all, if you delete all your contacts, google sync will restore it very quickly. However, when my app is adding contacts to the device, it's very slow (a few contacts per second). Even if I add almost empty contacts (with name only), it is a time-consuming process.

If I turn google sync off, importing 5000 contacts can take 1-2 hours (on HTC Magic). When google sync is on it can take up to 24hours. And this happens despite the fact, that application for the whole time is in the foreground, device is connected to charger and screen is on. I checked the logcat to make sure my app is adding the contacts the whole time, and it is.

I tried different methods and different devices. The results differ of course, yet manually adding contacts is always significantly slower that google sync. Is there any way that I can speed up the process? So that importing 5000 contacts will take less than an hour.