MB or OS problem - Locks up with more than one DIMM

[Texun]

This may be a MB problem but I need help finding the cause and am hoping Win2K can provide the info I need.

The problem is this:

I have an ACORP dual socket 370 board with dual PIII-700's that will lock up after an hour or two any time more than one cpu and one DIMM is used.

It runs fine with dual cpu's and one stick of anything - Kingston, Corsair, Crucial, dual or single sided PC133 memory.

It runs fine with one cpu and all DIMM's loaded with any of the above memory. (MAX 512MB)

It locks up hard with dual cpu's and any more than one stick of any of the above memory.

According to Intel the steppings are compatible for SMP.

Temps are never above 35C
I have removed all PCI cards and reinstalled Windows so many times I almost have the key memorized.
I am also running a generic HEC 250W PS

I hate generic PS's but I would have to gut my XP to test it with my Antec 430W, and from what I can tell the voltages are not that bad.

Dual cpu's and one DIMM
3.3v = 3.33
5.0v = 4.93
12v = 11.95

Dual CPU's and two DIMMS
3.3v =3.31
5.0v = 4.92
12v = 11.98

I tried 2cpu.com but got nothing.

Windows Event Viewer shows nothing ominous at the point of lockup. I am thinking that there is either a power problem or possibly some piece of hardware occupying a different block of memory once the other stick is installed. Is there any other place I could check in Windows that would tell me what is happening when it locks?

I'm stumped.. any ideas?

Update - I just tried it with 2x128 sticks and it locked up. I guess this blows the theory that it is a memory block. I had been using it with a single stick of 256 with no problems and thought it was related to a memory exceeding that.

 

[Iron Woode]

Run memtest. If that passes, then its time for PSU swap.

 

[mechBgon]

More PSU gets my vote. Make it something name-brand (Sparkle Power, Antec, Enermax). 300W units start around $33 shipped.

 

[Texun]

Thanks - I am running memtest now and will opt for the PSU depending on what it shows.

I appreciate the suggestions. One more question...... is there some "rule of thumb" for voltage variances? These are not all perfectly on target but they look very close to me. Maybe it is more MB specific.

 

[Iron Woode]

There is always some variation in voltages, however a better PSU will surprise you with more stable and correct readings esp. under load. That is where it counts the most.

I now use Enermax EG465P-VE (431watt) PSU for my power hungry systems. I would get a PSu like this because it makes a great future investment.

 

[Texun]

Thanks, Iron Wood.

I ran memtest and it passed with flying colors.

I am learning that SMP rigs can be very picky. I'll try another PS this weekend. I hope it works. If not, I will be stuck with W2K and a single cpu with all DIMMs filled - or both cpu's and a single stick. I don't like either option, especially since I have the hardware in hand.