RAM problems on Shuttle AK31a

[starcaptor]

Heys alls.

With RAM so dirt cheap now (I just nabbed two 256 PC2700 DDR sticks @ Microcenter for $23 each after rebate) I decided it would be cool to stock up now, and future proof my RIG for a while. I previously had two PC2100 sticks from Crucial, so when I fill up the (4) slots on my mobo, it would make a total of one gig of memory. But no matter what way I dice it, the computer is mad unstable with all the slots filled up, even if I run the memory asynchronously (100 FSB instead of 133) on my Athlon 1400. I lowered the CAS latency to 2.5, and that helps...for a while, but all I get are spontaneous reboots (spontaneously reboots to BIOS, I hear a click). I THINK it might have something to do with my Maxtor 60 gig HD...Always hated the brand, lol. But when I load up on just three sticks, it runs fine. Any suggestions? I remember reading in the past...I THINK...that since this was the first kt266a mobo to have 4 slots, and no other manufacturers would even go near 4 slots, that this mobo is unstable with 4 slots filled? hmm...:frown:

 

[Johneverd]

Sometimes motherboards get REALLY picky when you install memory in all of the slots. I couldn't say if this is the case with your specific model, but you might try an empty slot between sticks and see if that helps. Maybe you can borrow 2 x 512MB sticks, and if they work sell the 256MB sticks.

EDIT: What brand and wattage is your power supply? Lots of memory can suck a lot of juice, which a low wattage PSU might not be able to supply. If you have hardware monitoring see if the voltages dip under stress.

 

[starcaptor]

I thought about the PSU problem, so at the same time as buying RAM, I got a new Antec case/PSU kit, which included a 300W Antec SmartPower supply unit...mad quiet, definitely satisfied. Dunno if it was enough power, but upgrading to 350W was like $30 more. One thing to note...one of my four sticks is low density (modules on both sides). I tried everything, almost 8 different combos, leaving each slot empty each time, or two slots empty, and the like.

Edit: How can I monitor my mobos memory slots under stress to see if voltage goes down? Just boot up, go into BIOS, and look at hardware function? or use something like motherboard monitor?

 

[Johneverd]

It's hard to say if it's the 300w PSU or the double-sided DIMM, but my guess is that it's one or the other. When you mentioned that one of the sticks was double-sided that seemed like it. Double-sided DIMMs cause this exact problem when all slots are full. But then I looked at your system configuation and saw all of the devices that are hooked up to that 300w PSU, and now it's up in the air again.

Are there still 5 hard drives and 2 CD-ROMS hooked up? That might explain the click, as a hard drive could have low voltage. You might consider watching for a good quality 400-450w PSU deal at Anandtechs HOT DEALS forum.

Motherboard Monitor is a great way to check for voltage drops. Set it to monitor every 1 second, then check the HIGH/LOW screen or INTERVAL LOG to look for low voltages. The memory voltage itself may not be monitored, but the 3.3v and the 5v are, and the memory draws it's power from one of these rails (usually 3.3v). Check the 12v as well, as it runs the hard drives.

 

[DAPUNISHER]

I checked Crucial's memory configurator to confirm my suspicion that you need registered ECC when all the slots are filled like some of the Abits with 4 slots and sure enough registered ECC 2100DDR shows up on the list so that is most likely the problem.