View Full Version : Weird-looking DDR chip causing issues

02-06-10, 12:56 PM
Hey guys, my mom has an old AthlonXP 3500+ with 1.7GB PC3200 DDR RAM (that's 3x 512MB chips and 1x 256MB chip, all working great on an Abit AN8 motherboard using the latest BIOS revision. I recently bought her a 1GB chip (also PC3200) with which we have switched out the 256MB chip. I turn the computer on, and I get a POST code 40.

I looked this up in the manual, and this is what I came up with.

40 - Test 8259 interrupt mask bits for channel 2

I have no idea what this means, but it sounds to me like the second set of RAM chips is having an issue. So I take all the chips out, and reinsert the new RAM stick in DIMM1, and it works perfectly. Ok, so now I know it's not the RAM chip itself, so I put in another RAM chip right next to it in DIMM2. Same POST code. I read the manual a bit, and it said that sometimes when RAM-related errors occur, you have to reset the CMOS, so I did. Same POST code. Now keep in mind that this time, nothing is in the 2nd set of DIMM slots (which is what I assume this "channel 2" refers to.) So I tried putting the matching pairs in DIMM1 and DIMM2, and put the 1GB chip in DIMM4. Same POST code. So I took it out, and tried it in DIMM3. Same POST code. This looks like a compatibility issue. However, I've had different-sized RAM chips in here before, and it's worked fine.

Now here's the weird part - the problematic RAM stick looks nothing like any DDR stick I've ever seen - the chips are square, instead of rectangular, very much like what I've seen on DDR2 sticks. Could this be a different type of DDR chip that doesn't play along well with the others? If not, where could the incompatibility lie?

02-06-10, 02:00 PM
Yeah, you've got some screwy memory there. I don't know much about it but there are lots of cheap, high latency DDR sticks out there that actually use low speed DDR2 chips. Most likely because the low end DDR2 chips were cheaper to produce after DDR was phased out.

I've heard of these causing problems on many systems.

02-06-10, 02:26 PM
When I got it working, Windows booted up pretty darn quick. I didn't put it through any actual stress-testing though. My mom doesn't do any gaming, so I figured this might be enough for her needs. I'll be needing to buy another one it looks like.

02-06-10, 02:32 PM
Chances are good that the new stick has some really odd timings that don't match up with the other sticks you have. So when you mix them the board tries to run all the sticks at the same timings which causes problems.

02-06-10, 04:21 PM
Well I think I know what's causing the problem now. I looked at the chip again to get the model number off it so I could find the proper timings, and by chance I noticed "ECC Registered" written on a sticker on the back of the chip in blue ink. I seem to remember my dad saying something about ECC RAM causing problems when mixed with non-ECC RAM, so I did a Google search to be sure, and sure enough, I found an article saying some motherboards do not support mixing ECC/Non-ECC RAM. So that might be the whole problem right there.

BTW, I did search the model number just to find out who made the chip, and it's from a company called Infineon Technologies. Are they any good?

02-06-10, 08:40 PM
Infineon are chip manufacturer, like micron or samsung, rather than a product designer like corsair, kingston, crucial etc. Infineon may sell some dimms direct, but it's not their major business. They are usually considered to be positioned behind micron and samsung when it comes to DRAM chip manufacturing.

You won't need ECC on a normal desktop PC and yes, this would be what is causing the problem when mixing with non-ECC dimms. Either send it back or buy another stick for 2GB total.

02-06-10, 10:39 PM
i have some old ddr512 sticks laying around my house somewhere lol.