Memory bug in AMD processors. 2

[AndrewBaines]

I have a Slot A 900 MHz Athlon.
I have 3 256MB PC133 memory sticks.
Any 2 work in any combination of slots. If I add the 3rd, I get allsorts of errors and the PC resets.
I've read about a bug in AMD processors with large amounts of memory and downloaded a registry patch from AMD:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management]
"LargePageMinimum"=dword:ffffffff

I've tried this and updated everything possible (BIOS, AMD drivers etc etc) and I still get the problems.
So at the moment I'm stuck with 512MB and really need all 768MB as I use VMWare a lot.

Any ideas?

Thanks

Andrew

Andrew Baines
Chase International

http://www.chase-international.com

 

[etarhan]

Did you check if your MB supports this configuration?

 

[AndrewBaines]

Yes, it's an MS-6167. Fussy about memory but supports up to 768MB.
All the memory is Kingston and identical.
I should also add, I'm running Win2K server.
From the AMD site, Windows XP doesn't have the problem, but I need software RAID and Windows 2003 Server won't run on my PC (bluescreen)

Andrew Baines
Chase International

http://www.chase-international.com

 

[franklin97355]

This motherboard supports pc100 memory not pc133. there may be a problem with timing.

 

[shaner66]

Franklin - Correct me if I'm wrong, but I'm pretty sure that if a MB supports PC100 memory, it will also support PC133 memory with no problems.

 

[paparazi]

Unfortunately due to density and chip design some newer types of PC133 don't work correctly on older motherboards, sometimes multiple sticks don't work, sometimes they only read half there capacity, sometimes they just plain don't work at all.
The first PC133 to appear had no problems at all and would work just fine, so if you have a mate you can swop with????? his memory might be a differant configuration and work fine
Martin

Replying helps further our knowledge, without comment leaves us wondering.

 

[cdogg]

shaner66,
The specification for PC-133 states that its backwards compatible to work at 100MHz or 66MHz. So technically, you are correct.

However, many older PC-100 motherboards cannot read newer PC-133 chips. Why? Well like paparazi pointed out, chip densities have gotten pretty high. Because of this, the answer to whether a PC-133 chip will work in an older motherboard is always uncertain. It's a hit & miss deal.

Andrew,
If I understand you correctly, you're saying that every stick of RAM works fine by themselves, but not when all 3 are in at the same time, right?

If so, I suspect the 3rd slot on your motherboard is the problem. A lot of older AMD and Via chipsets had problems with the 3rd slot. Some were fixed in BIOS updates, while others were never fixed. Either it's a defect in your model or just on your motherboard.


~cdogg
[tab]"The secret to creativity is knowing how to hide your sources"
[tab][tab]- A. Einstein

 

[AndrewBaines]

Not quite, I'm using slots 1 and 3 at the moment with not problem. Yesterday I used slots 1 and 2 OK. It looks like its the amount of memory that's the problem.
I'm not sure if it's specific to AMD as I downloaded a patch as above.

Andrew Baines
Chase International

http://www.chase-international.com

 

[jfryer]

run memtest86 to verify your memory one stick at a time.
That will eliminate a fault with the actual sticks.

up the mem voltage by 0.1v (if your Bios supports this), it is quite possible that the higher density chips are sucking more power then the MB can cope with.

relax the mem timings a little so the MB has a bit more time to retrieve the data.

the final option is to by just 2 sticks of 512Meg RAM (not the most practical solution, but it will work)

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There is no magic, only onions
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[Eskimo69]

My computer only supports pc-100 I've tried thousands of chips all the way from 64mb to 256mb

 

[AndrewBaines]

Thanks all for your help.
Using 2 x 512MB not supported but a nice idea.

Memtest worked really well and showed up errors even when only 2 sticks were in use.
My BIOS has very little in the way of overclocking support so no voltage settings or anything.

It's turned out to be my motherboard (MS-6167) being incredibly fussy about types of RAM. I bought 3 x 256 MB PC133 from Crucial using their memory selector and everything works fine now. Even memtest gives a clean bill of health.

Only oddity is that I can't change the size of the page file - as soon as I click OK, the PC resets. I've got a maximum size of 3Gb and a dedicated volume so I guess I'll just have to live with that.



Andrew Baines
Chase International

http://www.chase-international.com