VNF4 not seeing all of my ram

[hectorrj]

Here's the problem: I have a Chaintech VNF4 ultra and I can NOT get this board to see more than 512 mb of ram in BIOS or Windows XP. I have 2 sticks of Corsair XMS pc3200, the newest bios (3/15/05) and MB drivers (6.54) for this board, and no matter what dimm slot config I try, Bios refuses to see both sticks. BUT it does go into dual channel mode... any ideas?

 

[GadgetBuilder]

Try running memtest86 on each stick separately by installing in slot 1, one at a time. Verify that they show up as the proper size during this test. Then, if they don't show up when installed in slots 1 and 2, slot 2's socket may be bad so try them in 1 and 3 (they should work OK in 1 & 3 but at 2T).

 

[Oceanic]

dont know about memtest i ran it and got 1300+ errors

dont think it works in dual channel mode lol

 

[GadgetBuilder]

Oceanic,

memtest86 shows no errors on my VNF4 system, which has been very stable (other than when trying new nVidia drivers).

Have you checked your sticks separately to see that each runs without errors when run alone?

 

[hectorrj]

Gadget,

I haven't tried memtest yet, but I wanted to see if my ram would work in slots 1 and 3 and sure enough BIOS saw 1 GB of ram, but at 2T, single channel. For some reason when I use slots 1 and 2 for dual channel mode, BIOS only sees 512, so maybe slot 2 is bad. But then again I tried putting both sticks in slots 3 and 4 and I get the same problem, Bios only sees 512, but runs them in Dual mode. So only slots 1 and 3 right not give me my 1 GB, wierd isn't it? Any suggestions?

 

[Peter]

Originally posted by: Oceanic
dont know about memtest i ran it and got 1300+ errors

dont think it works in dual channel mode lol

memtest is just a piece of software reading and writing to RAM. Its testing algorithms don't care how the system achieves that.

Will say, if memtest reports errors, then there are actual hardware errors.

 

[GadgetBuilder]

Hector,

I haven't tried 3 & 4 as you did but it seems like it should work. The fact that it detects only half the memory in 1&2 or 3&4 casts suspicion on the mobo or processor. There are two separate memory controllers built into the CPU, one for the odd slots and one for the even slots -- it seems like your even slots aren't working.

It would be a good idea to get out the bright light and magnifying glass and check the contact area on both sticks of ram for anything peculiar - any junk, paint, etc. stuck to the pins which might prevent contact with the socket. Similarly, look closely at all sockets on the board to ensure the contacts are straight and look normal.

Run memtest86 with the memory in the 1 and 3 slots (your only working setup) to verify that the memory is OK.

Try again with slots 1&2 populated, then try swapping sticks so the one which was in the odd slot is now in the even slot.

If none of this helps then try to borrow a processor from a friend to verify that the problem is not the CPU - this is a longshot since the CPU's have been very solid. However, there is little to go wrong on the mobo if the processor and memory sockets are OK. When you take the CPU out, look for any junk on the pins, bent pins, socket problems, etc.

If none of this helps you may have to RMA the board.

Best guess why it goes to dual channel is that BIOS sees the SPD info from the DIMM via the SMB so it expects the memory to be there but then the memory doesn't respond because of some fault so it can't use all the memory it thought was there. The surprising thing is that you don't get a POST error - you might check to be sure that you have the memory test enabled in POST.

 

[Peter]

This wouldn't be the first pair of DIMMs that won't cooperate in dual channel mode, but whose individual DIMMs run OK in single channel mode. Typically this is neither a CPU nor a board issue, but plain and simply bad RAM.