I have this issue too.
System:
Ubuntu 10.04 Beta 2, 64-bit CPU: Intel i7 860 MOBO: Gigabyte GA-P55A-UD3 GPU: ATI Radeon HD 5770 (1GB) MEM: 4GB DDR3 (PC-10600/1333MHz) HD: 2TB SATA2 (1TB x2)
Hope some of that information is helpful.
I have this issue too.
System:
Ubuntu 10.04 Beta 2, 64-bit
CPU: Intel i7 860
MOBO: Gigabyte GA-P55A-UD3
GPU: ATI Radeon HD 5770 (1GB)
MEM: 4GB DDR3 (PC-10600/1333MHz)
HD: 2TB SATA2 (1TB x2)
Hope some of that information is helpful.