8+ year-old PC strikes back: DDR2 issues now.

[nicologic]

Hello everyone.

After being rescued by some nice guys in this forum from a dilemma about installing a contemporary graphics card into my 8 year-old PC (and further problems that appeared), I thought that I was on a winning streak and decided to buy a couple of DDR2 RAM modules to improve a little bit my machine as it seems to have a new life now. That was supposed to be a much simpler operation so... what could go wrong...right? Well, here I am again...

I had previously read all I thought was necessary to do things right. My motherboard (Gigabyte GA-945P-S3) runs a Core 2 Duo E6600 2.40Hz and supports up to 4GB DDR2 667MHz, in 4 DIMM Slots with a dual channel configuration. I've always had 2GB (2x1GB modules), so I decided to add a couple more to top the 4GB (though I knew my 32 bit WinXP would only detect 3 plus something else).

As I read many threads on different sites explaining the bunch of problems that can occur when mixing different RAM's, I decided to buy just the same model I've been using since the very beginning of this PC's life (Kingston KVR667D2N5/1G) to avoid any kind of compatibility issues. Despite sharing the exact model number, the new ones definitely look different. They have a much lower profile (half the height, more or less) and, more significant, just eight chips in one single side, whereas the old ones have eight chips in both sides. I thought that it was due to enhancements in the manufacturing process for the 8 year age difference between them but the performance specs should remain the same.

I first mounted them in the 2 remaining DIMM slots in my motherboard, so the configuration was: OLDS (DIMM 1&3) - NEW (DIMM 2&4). The PC started with no problem at all and it displayed a new total 3.25GB from the System window in XP. But after a few hours happily using my "new" PC it crashed, which is very rare. On the next 2 runs it ended crashing aswell. Then, I ran CPU-Z and it displayed 4GB of RAM, but at just 335MHz instead of 667MHz. Looking up for more info i read that RAM speed could be changed from the BIOS, a whole new world to me. So I picked the motherboard's manual and began reading how to do it (yes, people like me have to study first...) and checked it make changes, but surprisingly it was already set to 667MHz. Then I decided to run a couple of free benchmarks (Novabench and PerformanceTest) to see anything. Novabench just gives a parameter regarding RAM, and with all 4 modules mounted it get a result of just over 2000MB/s. Then I run the same test without the 2 new modules and it scored a new max o 2900MB/s. From this point, I tried different configurations (combinig them, changing the slots, etc) and what I see is that both sets (old and new) have the exact same performance (2900MB/s), but when they're put together I get poorer results (2000MB/s) whatever the combination is (2 old + 2 new; 1 old + 1 new; 2 old + 1 new;...). Finally, the PC couldn't even boot with the four modules in it, just the same configuration gave me no problems until it crashed for the first time. Another weird thing is that the other benchmark (PerformanceTest) detects 4 GB too, but then, in the details, it displays 2 modules of 1024MB (old ones) and 2 of 512MB (new ones), and all of them at ridiculous 66MHz; yes, without the final 7.

Specs like latency and others cannot be changed from my BIOS, just the speed and voltage. So I don't know what else to try. Any advice will be muchly appreciated.

Thanks! (and sorry for the long text...)

 

[cb600fshornet]

CPU-Z saying 335MHz is fine, DDR stands for Double Data Rate, 335*2 = 670, which is as near as damn it to 667!


The matching pairs of RAM need to be in the right RAM slots for dual channel configuration (might need to check the motherboard manual for that one). However, dual channel memory really won't make any noticeable use in normal use, it'll just give you a couple more points in benchmarks. If you're having issues, simply turn it off in the BIOS. (It'll be mentioned as dual channel or "ganged" mode)


On a side note, you really have to be careful with PC components, static electricity kills them, so if you're messing about with the components a lot, make sure that you're grounded with an anti-static wristband (or simply touching an earth of some sort). Also ensure the power is completely removed before messing with the components (I'm sure you know already, just a cautious reminder).


If the PC crashes whilst the PC is in single channel mode, then you may have an issue with the new RAM sticks, claim them on warranty if they seem to be faulty, and get a refund or try another set!


Hope this helps, it's difficult to diagnose the problem when you're not on site, but this should send your investigation in the right direction!

 

[C0RR0SIVE]

Chances are the CPU memory controller is having issues attempting to run in dual channel because of the difference in RAM...

A lot of older memory controllers are incredibly PICKY about Single Sided and Double Sided RAM... YES THERE IS A DIFFERENCE. Never mix the two, a lot of motherboard manuals go over this, at least the ones I have from round 2005 do, and some boards just flat out don't work with one type over the other.

I suggest going and reading the book for your board to see what it says about single sided vs double sided, see if it can use both at the same time, and exactly what slots that they must be in.

If your book DOESN'T have a section at all about the differences and where the sticks should go, you need to run memtest86...

Start out running with just 1 stick in a slot... Once you get two passes, add another stick, repeat till all sticks are in. If a stick fails, remove it, and put another in, if it fails again, pull all RAM and test that single stick by it self. Fails again, bad stick, if it passes then you certainly have a memory controller issue with the two different types of RAM. This is why I don't buy based on model numbers anymore. They change parts all the time to make things cheaper and slap the same sticker on.


EDIT:

I just looked, according to that boards manual, it doesn't matter where supposedly... And it doesn't have warnings aginst using DS/SS mixed. So, first thing's first at this point... Put the double sided sticks in slot 1 and 3, put the single sided in slot 2 and 4 (slot closest to the CPU is slot 1). Then run Memtest86... If you get a failure, attempt reseating the sticks and repeat, then do what I said above to ensure your not having issues with a slot, or a stick in particular. Bad RAM happens more than one thinks.

 

[nicologic]

Hi guys, I've got some news.

After following your advice I ended up running memtest86 to check everything worked correctly. As I got my PC with just the two original RAM sticks in it, I ran the first test just in this configuration. Result: 0 errors, so the old sticks and channel 0 from my motherboard were all correct. Then I replaced tho old sticks by the new ones, in the same slots. Result: 0 errors, so all 4 sticks were correct. Then I placed these 2 new sticks in the other slots (channel 1) and ran the test with this only change. Result: 0 errors, so all the sticks and the slots seemed to be OK. Finally, the definite test, the combination of all 4 sticks, leaving the new ones in channel 1 and placing the old ones again in channel 0 (this is the original configuration that made my PC crash for first time). Result: 0 errors... uhm. After going to the toilette to watch my poker face in the mirror, I came back to my computer and decided to boot windows to see what happened. Everything looked OK, and here comes the best part: I ran the Novabench test (which displayed 2900MB/s when using one set of sticks, whether olds or new, and 2000MB/s when combining them) and this time it displayed 2900MB/s whith all four modules... second run to the toilette...

After a few seconds thinking I remembered I had changed the FSB processor value in the BIOS prior using memtest86, as I had read that could be one possible cause of my problems. Don't know why it was set to the lowest value (100), so I decided to set it to the highest (266). That might be the solution... to say something valid.

Situation now is that I seem to have a stable PC with 4GB in it, and if future problems occur I've also read that small voltage increases for the memory could be necessary, although considering all these tweaks and improvements I've recently made to my machine it feels like asking for an old man to run a marathon.

Like always, thanks for all your inputs, they have been hugely helpful. For the last few days I have learned more about computers than for all my previous life, though that wasn't very challenging I guess...

Thank you guys! Cheers!

 

[nicologic]

On a side note, you really have to be careful with PC components, static electricity kills them, so if you're messing about with the components a lot, make sure that you're grounded with an anti-static wristband (or simply touching an earth of some sort). Also ensure the power is completely removed before messing with the components (I'm sure you know already, just a cautious reminder).

I would not be so sure... I knew that I had to be careful when touching inner parts of a computer, but I thought it was just due to health concern . Now, from the tests and results that I've mentioned above there's one thing we all can certainly be sure of: I'm a damn lucky ignorant man...

 

[C0RR0SIVE]

It's highly possible that the RAM wasn't seated good enough... Years of dust in a slot can do that... No telling what happened.