Larger server with 12 cores. It will periodically hang with "some process: blocked for more than 120 seconds", the load avg will go to 30+, then a little while later, the load avg will fall to normal and life will continue as if nothing had happened.
~$ lspci
00:00.0 Host bridge: Intel Corporation 5520/5500/X58 I/O Hub to ESI Port (rev 22)
00:01.0 PCI bridge: Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port 1 (rev 22)
00:02.0 PCI bridge: Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port 2 (rev 22)
00:03.0 PCI bridge: Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port 3 (rev 22)
00:07.0 PCI bridge: Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port 7 (rev 22)
00:09.0 PCI bridge: Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port 9 (rev 22)
00:14.0 PIC: Intel Corporation 5520/5500/X58 I/O Hub System Management Registers (rev 22)
00:14.1 PIC: Intel Corporation 5520/5500/X58 I/O Hub GPIO and Scratch Pad Registers (rev 22)
00:14.2 PIC: Intel Corporation 5520/5500/X58 I/O Hub Control Status and RAS Registers (rev 22)
00:14.3 PIC: Intel Corporation 5520/5500/X58 I/O Hub Throttle Registers (rev 22)
00:16.0 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.1 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.2 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.3 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.4 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.5 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.6 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.7 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:1a.0 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #4
00:1a.1 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #5
00:1a.2 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #6
00:1a.7 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB2 EHCI Controller #2
00:1d.0 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #1
00:1d.1 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #2
00:1d.2 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #3
00:1d.7 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB2 EHCI Controller #1
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 90)
00:1f.0 ISA bridge: Intel Corporation 82801JIR (ICH10R) LPC Interface Controller
00:1f.2 IDE interface: Intel Corporation 82801JI (ICH10 Family) 4 port SATA IDE Controller #1
00:1f.3 SMBus: Intel Corporation 82801JI (ICH10 Family) SMBus Controller
00:1f.5 IDE interface: Intel Corporation 82801JI (ICH10 Family) 2 port SATA IDE Controller #2
01:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection
02:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection
03:00.0 RAID bus controller: Silicon Image, Inc. SiI 3132 Serial ATA Raid II Controller (rev 01)
06:04.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200eW WPCM450 (rev 0a)
Been experiencing this off and on for about a year. Does seem to be heavily tied to quantity of IO.