A7M266 Instabillity when both DIMM Slots populated....HELP !!!

[Ratters]

Just built a new AMD 1.2 GHz 266 FSB system using Asus A7M266 Mobo. I also bought two Crucial PC2100 256MB SIMMS. Problem is the system is very unstable, keeps on coming up with various .DLL file problems and the odd VXD Blue screen error when both SIMMS are fitted, and I start using various programmes ?? System seems to run a lot more stable when only one 256MB SIMM is fitted (tried both individually in first DIMM slot...No problems) ??? I tried various Voltage settings through VI01 jumper, 2.5, 2.7 & 2.8 Volts.....Didnt help, same problem. Does anyone know the cause, or have a solution to this Problem ???

PS. What is the optimum or most stable Voltage setting for the Clock generator, Jumper VI0 for the AMD 1.2GHz 266FSB Processor....3.30, 3.45 or 3.56 Volts ????

 

[cipher00]

There's a link out there to LostCircuits that goes into the A7M266. I seem to recall that there's an undocumented setting with the VIO jumper that causes problems -- the ram is very finicky about voltage. I believe that you must remove the jumper entirely; can't recall for sure, but this might help. Read the review, if you haven't already, and see if that helps.

Be sure to post back if/when you solve the problem! Good luck.

 

[MS]

if you increase the VIO for the clock generator, you actually run it faster, at 3.45 V your 100 MHz reference signal will be 101.3 which is not seen by the system, BIOS or any other internal measuring device that would, e.g. report back to to CPUID. Basically, your system runs faster than you think it does, an old trick used by ASUS to get their benchmarks faster (because the system runs faster but doesn't show it).

Regarding the stability problems, the first step you should take is to flash the BIOS to the latest version to allow you to manually set the parameters (the original BIOS has the setting but does not execute them).

Make sure that you have the tRAS set to the highest value, it won't have any impact on performance but increase stability.

If you have any questions about the meaning of the specific BIOS settings, I have put up a "relatively" complete guide at http://www.lostcircuits.com/advice/bios2/1.shtml

regards

 

[Ratters]

Tried all of the above (except tRAS ??? where is this adzactly). Currently running with single PC2100 256MB SIMM (tried both individually...both worked fine)currently using VIO1 at 2.7 Volts & VIO at 3.45 Volts (tried all other settings and combinations)and seems to be stable, except when I used VIO at 3.45 Volts ???? Every time I used two SIMMS I had problems, even at 2.7 / 3.30 Voltage settings ???? Maybe this Mobo just doesnt like two PC2100 SIMMS at same time Using Norton Diagnostics Memory Test I would always get a Fail when using both SIMMS, while using a single SIMM (tried both individually) I would always get a pass !!!!