Does anyone have more than 4 GB RAM running?

mulda

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Mar 24, 2007
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Hi,

I recently got my GA965P-DS3, and I wanted to add 2x2 GB RAM DDR2-667 (SAMSUNG) and 2x1 GB RAM DDR2-667 (MDT), a total of 6 GB RAM.
Unfortunately, it didn't work out: With the initial boot of 6 GB RAM, the machine worked slowly and instable. The POST screen took like 2-3 minutes to initialise, and when it finally came to the step of booting linux, I had to wait 5 minutes again. The machine finally freezed during the kernel boot process while "freeing unused kernel memory".
I tested the system with a single 2 GB stick: Works flawlessly. I checked the other 2 GB stick: no problem either.
When I add both of them together (tried different RAM banks, with and w/o Dual Channel, BIOS settings, changed RAM frequency, etc.), the system runs slowly and is nearly incapable to use.

My question: Does anyone have more than 4 GB RAM running? If yes, which board/chipset/RAMs? I suspect the board, because when I added both sticks to two different boards with the 945 chipset family, it works without problems. But the 945 chipset only supports 4 GB RAM, so just 3.2 GB RAM would be useable.

Thank you for some recommandations :)
 

mulda

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Mar 24, 2007
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Yes, on Windows. 64Bit only enables you to assign more than 4 GB RAM to a single process (which is actually useless), it doens't affect the whole system.
Linux (32Bit) supports up to 64 GB RAM.

Regardless of that, my problem already exists before an OS is even loaded ;)
 

mulda

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Mar 24, 2007
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Thanks, interesting point, I'll check this.

No you're wrong, it's a common hoax that you need a 64bit system to use more than 4 GB RAM - and I think I know if I have installed 32 or 64bit Linux ;)
It is only meant for a direct addresing to a specific process, you can definitely have 64 GB RAM with your 32Bit OS, with the only limitation that you can't address more than 4 GB to a process, which is, as said, totally unneccessary.
 

Mondoman

Splendid
..., it's a common hoax that you need a 64bit system to use more than 4 GB RAM ...
It is only meant for a direct addresing to a specific process, you can definitely have 64 GB RAM with your 32Bit OS, with the only limitation that you can't address more than 4 GB to a process, which is, as said, totally unneccessary.
It's a bit more complicated than that. In order to address more than 4GB physical RAM in a 32-bit OS, various hardware/software extensions need to be used; unless the OS components, programs and the drivers interacting with the kernel were all designed for this, incompatibilities and/or performance slowdowns (e.g. because of multiple added levels of indirection) occur. That's why Win XP (32 bit) and Vista (32 bit) are limited to 4GB physical RAM (and in practice around 3GB because of other hardware occupying address space).
Interestingly, MS has limited even 64-bit Vista Home Basic and Premium to 8GB and 16GB physical RAM, respectively, presumably for marketing reasons (business editions currently can access 128GB of physical RAM).

Like you, I suspect your MB for your problem. Hopefully, it's just a BIOS issue and will be fixed. My guess is that the consumer MB makers are not putting much effort into verifying proper MB operation w/more than 4GB, since consumer Windows has had the 4GB limit.
Another possibility is that it could be your graphics or other add-on card being incompatible with >4GB addressing. IIRC, they're supposed to sign-extend their 32-bit addresses so they end up at the top of whatever memory range they're running in, rather than smack dab in the middle of RAM under the 4GB boundary.
 

mulda

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Mar 24, 2007
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Another possibility is that it could be your graphics or other add-on card being incompatible with >4GB addressing. IIRC, they're supposed to sign-extend their 32-bit addresses so they end up at the top of whatever memory range they're running in, rather than smack dab in the middle of RAM above the 4GB boundary.

Well, I have to admit, the graphic card we used was indeed an old PCI card from 1997. If that card is responsible for the memory problem I would be damn happy and also pissed off about myself, because I didn't take a PCI-E card with me to the data center.

I'll definitely test this option, thank you! :)