dib0700: Any known issues with CPU usage?

I've been wondering about this for a while, and am reasonably convinced there may be a problem in the linuxtv version of the dib0700 (or one of its submodules).

I've got a Hauppauge WinTV-NOVA-TD-500 (84xxx) PCI card (http://www.linuxtv.org/wiki/index.php/Hauppauge_WinTV-NOVA-T-500 - which seems to have been hacked incidentally).

Today I installed a 2.6.29.1 kernel with the dib0700 module etc. installed (and it all works fine, barring the remote control), which shows in top:

top - 21:25:03 up 4:06, 2 users, load average: 0.00, 0.00, 0.00
Tasks: 144 total, 1 running, 143 sleeping, 0 stopped, 0 zombie

However, if I do nothing else except install the latest linuxtv drivers from mercurial and then reboot:

top - 21:54:45 up 30 min, 3 users, load average: 0.50, 0.53, 0.43
Tasks: 147 total, 1 running, 146 sleeping, 0 stopped, 0 zombie

You can see the load average is significantly higher. (and if I forcibly remove the module, the load average will eventually drop to 0)

The only user-facing difference I'm aware of is that the linuxtv version supports the remote control, whereas the kernel version doesn't - would this cause a big jump in CPU usage, or is there something else going on here?

If there's any more info needed to get to the bottom of this, don't hesitate to ask :)

Thanks for your help,

Alex.