Fresh install of Win7 x64 - constant BSODS - minidumps analyze needed

Looking for merciful soul that would help me analyze few BSOD minidumps :)

I have updated the BIOS, have latest NVIDIA drivers and all works OK even under load testing. But from time to time (1-3h) a BSOD with random message will appear.

System info

Windows 7 x64 RTM
AMD Phenom II X4 820  
8GB of DDR3 RAM(4 x 2) Kingston   
Gainward GTS 250 512MB DDR3  
HDD1: Samsung SATA 320GB  
HDD2: Samsung SATA 1TB  
MOBO: Gigabyte MA770T-UD3P  

Memory diagnostic does not show any problems...

You can get the memory dumps (link is dead now)

Any suggestion on how to trouble shoot this further?

UPDATE

WinDbg !analyze:

Probably caused by : ntkrnlmp.exe ( nt!KiInsertTimerTable+13b )

Blame MS? :) I guess I'll start swapping RAM in and out.

More details:

SYSTEM_SERVICE_EXCEPTION (3b)  
An exception happened while executing a system service routine.  
Arguments:
Arg1: 00000000c0000005, Exception code that caused the bugcheck  
Arg2: fffff80002c8894b, Address of the exception record for the exception that caused the bugcheck  
Arg3: fffff8800b148bc0, Address of the context record for the exception that caused the bugcheck  
Arg4: 0000000000000000, zero.  

Debugging Details:
------------------


EXCEPTION_CODE: (NTSTATUS) 0xc0000005   - The instruction at 0x%08lx referenced memory at 0x%08lx. The memory could not be %s.

UPDATE 2

memtest86+ showed an error with overnight testing - time to swap out the rams :) hopefully its them not the mobo or cpu.

082309-14742-01.dmp indicates that you have faulty hardware:

CONTEXT:  fffff88008876fc0 -- (.cxr 0xfffff88008876fc0)
rax=0000000000000001 rbx=fffffa800953ec20 rcx=0000000000000001
rdx=f7fff880009ea868 rsi=00000000000014e0 rdi=fffff880009e7180
...
nt!KiInsertTimerTable+0x13b:
fffff800`02cd094b 488b42f8        mov     rax,qword ptr [rdx-8] ds:002b:f7fff880`009ea860=????????????????

Note that rdx=f7fff880009ea868. That's a non-canonical x64 kernel mode address. Valid x64 kernel mode addresses range from 0xffff800000000000 to 0xffffffffffffffff. The '7' digit looks like a single bit error. All of the other dumps display the same stuck bit. I'd try swapping out your RAM first and running Memtest86+, but it could be the motherboard or CPU as well.

Also, the crash associated with 082309-24663-01.dmp occurred while executing VirtualBox.exe, but I think that's a red herring. Nonetheless, virtualization software is worth mentioning when posting about a bugcheck.