SuperMicro H8DC8 - memory

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liqnit
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SuperMicro H8DC8 - memory

Post by liqnit » Wed Jan 30, 2008 4:04 am

Hi
when installing Radeon X1650 on the board with 4GB of memory i can only see 2GB.
When installing Radeon HD2400Pro i can see 3+ GB .

My spec:
Board SuperMicro H8DC8
CPU Opteron 275 *2
VGA - PCI-Express Radeon X1650Pro 512MB DDR2
Radeon HD2400Pro 256MB
HD - WD 10K 36GB
Memory : Wintec EG ECC 4 * 1GB DDR400
PSU 560W.

I installed Windows XP SP2 with latest updates.

Tried all the latest Drivers from ATI\AMD. Catalys 8.1 and with Display driver only.
Any ide could be great.

SAMSAMHA
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Re: SuperMicro H8DC8 - memory

Post by SAMSAMHA » Sun Feb 03, 2008 3:05 pm

xp is a 32bit OS so it can only take max of 2.5~3gb, depending on your moobo and system. If you want to use and see all 4 gb, you would have to go to 64bit os.

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Re: SuperMicro H8DC8 - memory

Post by DMB2000uk » Sun Feb 03, 2008 3:26 pm

The reason that you aren't seeing all of the available ram is that 32bit OS's can only see a maximum of 4GB. From this four gig, things like video memory is also included.

That is why you can see more RAM with the 256MB video card.

Like SAMSAMHA said, if you really want to use all 4GB then you will have to get a 64Bit OS (like vista).

Dan
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Re: SuperMicro H8DC8 - memory

Post by liqnit » Mon Feb 04, 2008 11:55 pm

DMB2000uk wrote:The reason that you aren't seeing all of the available ram is that 32bit OS's can only see a maximum of 4GB. From this four gig, things like video memory is also included.

That is why you can see more RAM with the 256MB video card.

Like SAMSAMHA said, if you really want to use all 4GB then you will have to get a 64Bit OS (like vista).

Dan
thnks for both replies i know about the 32Bit limit , but what bothers me is when i use the first VGA card i get 1GB more of memory.
I also did some further testing and found that some BIOS paramers can make a big chnage in memory - "Map memory hole".
Anyone is familiar with that option in BIOS?

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Re: SuperMicro H8DC8 - memory

Post by Methious » Tue Feb 05, 2008 9:05 am

Whole Article :http://www.dansdata.com/askdan00015.htm

By default, an all-64-bit PC will still have the standard big holes in its memory from three to four gigabytes. This is the lowest-hassle way to deal with the problem - just install more than 4Gb of memory, and live with the fact that your 8Gb PC with a 768Mb graphics card only actually has seven-point-not-much gigabytes of visible RAM.

One advantage of this is that you can still boot a 32-bit OS, if you want to. Another is that this vanilla configuration is most likely to actually work. Cleverer memory configurations aren't necessarily properly supported by hardware, operating systems and device drivers yet.

If you don't care about these factors, though, there are two ways to get the lost memory back.

Some 64-bit motherboards these days give you an option for "memory hole remapping". That moves the fourth-gigabyte MMIO memory holes higher into the 64-bit address space, probably way above the maximum RAM you can physically install.

Many other 64-bit boards, though, are even smarter, and can leave the memory holes where they are and remap (at least some of) the physical RAM out from under the holes and up past 4Gb. This process is often entertainingly referred to as "memory hoisting", and it used to be the preserve of server motherboards. It's been showing up in more and more desktop mobos, though. And on some of them, the memory-hoisting BIOS setting even works, and doesn't horribly crash the system as soon as something tries to use the remapped RAM.
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