anyone had this problem?

I've got a Lenovo T61p, been running Win7 beta, then RC, now RTM Enterprise trial, all 64bit, with just about no problems for a long time now.
Have you looked into the Intel Turbo Memory? I had to disable its driver under Vista Ultimate 64bit, as from time to time system would just get unresponsive; sometimes for a just a bit, and sometimes long enough to force a restart via the power button.

Is this a clean install of Windows 7? I would try that, if you have a good backup, and access to install disks for your apps. Clean installs almost always run "better" (knock on wood) than upgrades in my experience.

You can get updates for the bios through Lenovo's support website for your specific model. It's very easy. Just go to Lenovo.com and look for support and follow links to your line (thinkpad) and model. Then you will find many driver and bios updates that are available. They also have a special section for Win 7 compatible drivers (note, they still call them W7 beta drivers but they are better than the Vista drivers for their respective functions, if you are using W7. You should install the latest bios and update all major drivers, especially the ones with W7 beta drivers applicable to your system.) You can do the drivers after you upgrade to W7. The bios update should be done before.

Once you have upgrade the bios, W7 should get you up and running quite well without any additional drivers, but if you update with the new Lenovo drivers, they will enable and restore some of the special Thinkpad functionality and hot keys, and possibly enable better power management. So it's a good thing to do, imo, except you would probably be well advised to just forget about installing Lenovo's Access Connections, as W7's native network management is superior, imo.

Btw, as you may see from my specs, I'm running 7 on a T61p and it's running quite awesomely for me. Wouldn't go back to Vista or XP if you paid me a lot of money.