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Stability issue with greater RAM


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Recently I reinstalled 2003, having some unrepairable problems in the system due to hardware failures and bad maintanence practice and I managed to get ahold of another 512MB* of RAM to add to the existing 768MB. When I did do this though, I found the system to go completely unstable. Originally I put it down to the 256MB stick being the cause as it's single sided while the two 512MB sticks are double sided. This was quickly proven false when I removed the stick and ran at 1024MB. Even then it was completely unstable as if it couldn't handle any more than 768MB.

My next thought was it was the new stick of which I took back to the store today and got it exchanged. When the system continued to malfunction, I repeated both the previous steps and then tried removing the old 512MB stick and adding the new one as a process of elimination to make sure it wasn't that screwing the system up. As expected it runs fine while used alone with the 256MB stick which proved neither of the three sticks are faulty. So I've put it down to something funny playing up with the hardware (ie. the two 512MB sticks are fighting over the 256MB stick like a retarded circuit board love triangle) or the system isn't recognising the extra RAM properly. For arguments sake, I'll go with the latter for the final step of elimination**.

I am prepared to reinstall to rectify this problem if it is the only way, but surely there must be some way to fix it without blowing the system away. Anyone have any idea of what's going on?

*Using DDR400 for all three sticks as it's an old 32bit AMD system

**If it's a hardware problem (which I doubt it is at this point) I'll have to cut my losses and that dream 64bit system is going to come a little sooner than expected *waves goodbye to $2000*

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What motherboard? What memory sticks? The more information the better.

Also, try testing your sticks with memtest86+. Individually at first (make sure none is bad), then you can try combinations (to see if they don't play nice together). If the amount is says when it posts is right, then it's recognizing it.

There's just not enough information to tell.

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I figured someone would need more information, not a problem. The motherboard is a Gigabyte 7VT600P-RZ Running an AMD Athlon XP 2600+ (the old Athlons, not the 64bit ones). The old 512MB double sided stick is a Ram Bo VSS3200/512 512MB DDR PC3200 CL2.5. The new 512MB double sided stick is a Apacer 512MB UNB PC3200 CL3. The 256MB single sided stick is a Veritech VM256M DDR400 VT400F/256 0504.

Looking at these number, I have no idea what they mean, but I do notice a consistancy with the CL thing whatever that is, it looks like the CL2.5 may be incompatible wth the CL3. I'll do some research to see if this is the case, if not I'll do a memtest on all three then report back.

Edited by Sekkira
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Yep, that seemed to be the problem. Grabbed a new stick of 512MB Kingston and it works fine with the current 512 stick. The system goes unstable with the 256MB stick in there, but that was expected as it's single sided. As long as the two 512MB sticks work together it's fine.

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It's likely unstable with more than one RAM module, because of a motherboard circuitry issue.

But it's even more likely because of latency setting issues or chipset issues. It's likely that you're forced to run the RAM at performance crippling settings, just for data corruption to stop occurring!

Edited by RJARRRPCGP
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I doubt it's the latter, the ram should be running with a 2.5 CAS Latency, as said before the other new stick of ram was running at 3, putting them out of synch. You're probably right about it being a motherboard circuitry issue, but I really can't diagnose that, don't have the tools. Even so, it runs fine as it is now and this was the last upgrade I'm doing to this comp anyway.

If I needed to get a new motherboard, I'd be going for the whole box and dice, getting top of the line Mobo, CPU, GFX Card and 2gb of ram. No real driver support for 64bit (for what I'm doing, I'm well aware 64bit tech is nothing new) at the moment, but something like that would last me years.

So yeah, thanks for the help with this guys.

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I doubt it's the latter, the ram should be running with a 2.5 CAS Latency, as said before the other new stick of ram was running at 3, putting them out of synch. You're probably right about it being a motherboard circuitry issue, but I really can't diagnose that, don't have the tools. Even so, it runs fine as it is now and this was the last upgrade I'm doing to this comp anyway.

If I needed to get a new motherboard, I'd be going for the whole box and dice, getting top of the line Mobo, CPU, GFX Card and 2gb of ram. No real driver support for 64bit (for what I'm doing, I'm well aware 64bit tech is nothing new) at the moment, but something like that would last me years.

So yeah, thanks for the help with this guys.

It's likely because that RAM can't handle stinkin' CAS 2.5! It may require 3.0-4-4-8 or higher!

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It's likely because that RAM can't handle stinkin' CAS 2.5! It may require 3.0-4-4-8 or higher!

Correct me if I'm wrong, but isn't it the case that the lower latency of anything, the better?

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It's likely because that RAM can't handle stinkin' CAS 2.5! It may require 3.0-4-4-8 or higher!

Correct me if I'm wrong, but isn't it the case that the lower latency of anything, the better?

Yep. And most DDR 1 will do at least 2.5-3-3-7 or 2.5-4-4-8.

But I recommend Memtest86 to test the RAM. Run Memtest86 after applying setting changes.

I recommend that you try these settings:

2.5 (CAS)

3

(for both tRCD and TRP)

3

7 (tRAS)

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  • 2 weeks later...

Check the amount of L2 cache on your CPU. If you install more RAM than the CPU cache you will get unstable results from a shortage of addresses.

I read recently here that the L2 cache should ideally be 2x the installed RAM.

For me limiting the amount of RAM thusly resulted in a smart increase in performance and stability.

Also, RAM performance for the whole amount will be whatever the slowest CAS is with mixed RAM. (From Crucial.)

Dick

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I read recently here that the L2 cache should ideally be 2x the installed RAM.

Dick

Dick, you need to read more carefully. :whistle:

Most desktop CPU's of that age only came with 256/512kb of L2 cache. So 2x less would be 128/256 kilobytes for ram. Not going to work seeing how 2003 minimum is 128 megabytes (which is nuts in itself).

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Most desktop CPU's of that age only came with 256/512kb of L2 cache. So 2x less would be 128/256 kilobytes for ram. Not going to work seeing how 2003 minimum is 128 megabytes (which is nuts in itself).

That is precisely my experience w/ my chip which has L2=512.

Although the system BIOS will recognize 512 MB of RAM it will run much better (faster) w/ 256 MB and NO stability issues. I was expecting big things with the second 256 MB. Alas, no joy.

By the way 384MB performance is good too. I just used the 128 MB stick in another box or I would have reinstalled it w/ the 256.

All memory is matched for CAS (2) and Manufacturer.

YMMV

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