Can I get all my 4 GB RAM working?

[ranbic]

Hi

I have 2 XMS2X2048-6400C5, DDR-2 800MHz working togheter in slots 1 and 3 of my P5B-Premium Vista Edition now. I have 2 problems:

1)During boot, system only reads 3006MB of RAM, and so does my Vista 32bits
2)According to Everest 4.2, the velocity is: DDR2-800 (400MHz). Only 400MHz

Could I make the memories work better togheter? If so, what should I do?

Thanks, a lot

[madman045]

To have windows see all 4Gb you will need 64bit edition, I have 4GB in my laptop, but only 3.2Gb show in windows due to other factors, such as if you have a 512mb graphics card, also minus that from the 4Gb you have.

[charleski]

DDR-2 works at twice the frequency of the bus. So 800MHZ DDR-2 RAM uses a 400MHz bus.

[callius]

well not quite true you can make windows see all 4gb of ya ram, though windows will onlu utilise approx 3,200 or so. Windows 32bit is limited to 4gig total, and thus takes approx 1gig for the system which leaves 3gig showing to you
If you add /PAE on ya boot string it will show you 4GB in windows, but the actual way windows will work will not change unless you use PAE enabled app's aka MS server apps. SQL and i think exchange i forget.

Though some motherboards DO have an issue with 3GB max ram, which it sounds might be your issue, id check with the MOBO manufacturer may even need bios flash or could be a max on the board.

[dangel]

/PAE is a hack and doesn't change the fact that 32bits means 4 gig of addressing - in other words ALL the devices on your system require some of that address space, and so you can't address all of the memory as a result. Get Vista 64 if you want to do things properly - it works as well as the 32bit version for me. No hacks, plenty of address space, all your memory.
P.S. do a search on here this has been answered exhaustively in many, many threads!

[ranbic]

many thanx to all of you, for now I know what´s happening!
I´m seriously considering using Vista 64, since it doesn´t seems to be that bad when it comes to compatibility issues (CorelDRAW, some games, Nero, iTunes, and some others not so important-right?!)

[ranbic]

dangel, I did do a survey before posting, but perhaps not in the exactly proper way - didn´t get much answers

[dangel]

Originally Posted by ranbic

dangel, I did do a survey before posting, but perhaps not in the exactly proper way - didn´t get much answers

Sorry - wasn't having a go matey just pointing out there are a few threads that answer this very well

[Yellowbeard]

Regardless of the OS used, the bios should still see all of the RAM at post. On this particular MOBO you have to enable memory remapping to see the full amount of memory at the bios level. After that, as noted, you need a 64 bit OS to fully utilize all of the installed system memory.

[ranbic]

OK, man! I´ll look for memory remapping and post the results, thanks

[ranbic]

Yes, it worked, now I see 4096 at bios level

One more thing, Corsair has sent an email inviting me to "adjust the DDR voltage to the required 2.75v in bios". However, my kind of memory was "tested in 1.8v at JEDEC standart latency settings" (TWIN2X2048-6400C5DHX pdf file). Can I change DDR voltage fearless?
t.h.a.n.x.

[Yellowbeard]

It appears that you were given the wrong voltage. On the DHX memory, you can run it safely to 2.1v if needed but, 1.9v is all you should need if 1.8v is not stable.

[ranbic]

Guy, wrong voltage! Geerr

Friend, as far as I now I get the PC running in stable mode, no problems. Here it goes:

Core 2 Duo E6600 2,4GHz | ASUS P5B Premium Vista Edition | 2x2048 DDR2-800 Corsair XMS2 | 400 GB Seagate | GFORCE 8800 GTS 320MB | PSU Spire 650W | Vista 32 bits

And this config in Bios:
mem volt = auto; config dram timing by spd = enabled; dram frequency = auto
Should I change any of this?
And guess what, now Vista shows only 2047MB, while at bios it appears more... I´d rather Windows with 3GB than a bios with 4, of course.. Could I expect it to be 2GB? Or I´d better change memory remapping again?

I can´t thank you enough

[Yellowbeard]

You may need to contact ASUS but for now, I would disable memory remapping and you will have more usable memory.

[ranbic]

Yes, the missing memory came back.

Just one more thing, and then I´m gone, I promise.
Is it ok in bios:
mem volt = auto; config dram timing by spd = enabled; dram frequency = auto

merci

[Yellowbeard]

Originally Posted by ranbic

Yes, the missing memory came back.

Just one more thing, and then I´m gone, I promise.
Is it ok in bios:
mem volt = auto; config dram timing by spd = enabled; dram frequency = auto

merci

If your system is stable, then yes, these voltages are good. If it is not stable or, if you choose to overclock, then you may need to make some changes.