Feisty Upgrade - First Problem

We recently updated all our Ubuntu machines from Edgy to Feisty. Updating went smooth, apart from a few problems.
The first problem was that X was freezing at random intervals. Xorg log mentioned nothing special, but the GDM log did:

Error in I830WaitLpRing(), now is 7023360, start is 7021359
pgetbl_ctl: 0x3ffc0001 pgetbl_err: 0x0
ipeir: 0 iphdr: 1810000
LP ring tail: 9b38 head: 938c len: 1f801 start 0
eir: 0 esr: 0 emr: ffff
instdone: ffc0 instpm: 0
memmode: 306 instps: f0000
hwstam: ffff ier: 0 imr: ffff iir: 0
space: 129100 wanted 131064

Fatal server error:
lockup So I did the only thing I could think of: I removed the Videoram lines from xorg.conf. And the freezes seem to have stopped.