[fikle]

I would really appreciate some insight into this problem. I have been scouring forums for the last few days with no success. I am attempting to upgrade my PC's memory.

The machine is an Intel Celeron 2.4ghz running windows xp home edition

The Motherboard is made by MSI and is model number MS 6787 version 2. there is a link to the specs and the manual here:

http://global.msi.co...mp;maincat_no=1

The motherboard has two 184 pin slots, and came fitted with one 512mb DDR stick (333Mhz-CL2.5). I am attempting to replace this with two 1Gb sticks. They were bought from Novatech, and are type PC2100, 266mhz, 2.5v DDR. I have consulted the motherboard manual and it lists PC2100, 2.5v as being compatible. One thing that I was struck by was that the manual mentions 266mhz speed ram, but not 333mhz, which seems odd seeing as that's what the machine came with.

We I installed the two 1gb sticks, the total ram displayed in both BIOS was only 1gb, suggesting that the system is only rating them as 512mb each. I have tried each stick individually, and in each case it shows 512mb (in both BIOS and in XP). They even work fine if used in conjunction with the old 512mb, yet, with any combination of the three of them I still only get 1gb. The manual for the motherboard states that it can support up to 2gb. I have updated my BIOS to the latest version, and reset BIOS to optimum settings, but with no joy.

I ran a program which was suggested on another forum, which checked the computer and displayed detailed systems information, but I can't for the life of me remember what it was called, other than that it started with a C and had three letters (and maybe a dash betwen two of them?) Anyway the significant point of this ramble was that this program showed my memory as 1.5gb (at the time I had one 1gb and the old 512mb stick installed). As this program can see that the memory is all present and correct, I think I can rule out the possibility that the chips have been programmed with the wrong capacity. So why can't BIOS or Windows see it?

Any ideas would be met with intense gratitude.

Alan

PS - I've tried to supply as much detail as I can, however I apologise if I've missed out anything really obvious.

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This board has onboard graphics which may be where the missing memory has gone. Most boards set to Auto will scale the amount of graphics memory used depending on how much physical memory there is installed. This may be where the missing memory has gone.

[Neil Jones]

This board has onboard graphics which may be where the missing memory has gone. Most boards set to Auto will scale the amount of graphics memory used depending on how much physical memory there is installed. This may be where the missing memory has gone.

[The Skeptic]

Try to reset the BIOS by disconnecting the power and taking out the cmos battery for 10-15 minutes. Boot after reinstallation and do not change any settings except for time and date.

From the link provided in your post download Via Chipset (4 in 1) driver and install it.

[fikle]

Thanks for the advice, I've tried resseting the BIOS in the way you suggested Skeptic, and updated the chipset, but to no avail. Any other ideas?

Currently running the machine with two 1gb sticks. BIOS and windows report that there is 1gb in total. I don't think that the graphics card is likely to account for a whole gigabyte.

Alan

[The Skeptic]

Just one more test. Please open Task Manager, click on .performance and report Physical Memory. How much is Total and how much is available.

[fikle]

Total = 1048048
Available = 492772

This is with 2gb installed


Meanwhile I remembered the software I used which could see all my ram - it's called CPU-Z

According to CPUZ I have 2048 MByes of DDR Ram. You can also look at each slot individually. Interestingly it says that one of them has a max bandwidth of PC3200 (200 mhz) and the other has a max bandwidth of PC2700 (166Mhz). I don't know whether this is reffering to the memory sticks or the motherboard slots. If the latter, why would they be different? It shouldn't be the former as both sticks are the exact same make and model.

Cheers for sticking with it.

Alan

[The Skeptic]

Since Windows is the the software that manages the the memory, any other program is irrelevant. Your motherboard, according to the user manual, supports memory speeds of 200 and 266 MHz. If you install a faster module, say, 333 or 400 MHz it'sd speed will be reduced by the computer either to the level supported by the motherboard or the speed of the slower of the two modules.

I honestly don't have an answer to your problem. Old motherboards supported up to 512 MB per slot, but yours should be different. I'll do some research and if I find an answer I'll post back.

My feeling is that there are three possible causes:

1: The BIOS limits memory volume. Please look carefully in the manual and the BIOS menu and see if there is anything that could cause that.

2: In older motherboards memory and cpu parameters were set by jumpers and dip switches. Please look in the manual and see if there is such a limiting mechanism.

3: There is some incompatability between the memory modules and the motherboard. Could you get another 1 Gig module? If yes, insert it into your computer and let's see what happens.

[fikle]

Thanks I'll have a look into those. The two new modules I am installing run at 266Mhz, so that should be fine, but what is strange is that the 512mb module that cam installed when I got the computer new runs at 333Mhz so theoretically there should have been more of a problem with that one!

I'll post back when I've done some mroe research.

[The Skeptic]

The fact that the old module is faster makes no difference. The computer simply lowers it's speed to 266 to make it compatible with the other. Obviously it's better to have identical modules. This ensures that latencies and other parameters do not create problems between the two modules. Speed, however, is not a problem.

[skie_m]

Many RAM manufacturers allow for backward compatability with their RAM modules ... The case with this being that the 512 MB 333 stick was cheaper due to price cuts or was just plain available and on-hand ... This is why your 333 MHz ram stick was functional in your computer.

Your memory controller will also automatically adjust your memory clock speeds to match that of the LOWEST speed memory installed.


That having been said ... I've had problems with MSI and specifically the VIA chipset in the past with not recognizing high density RAM (memory modules with chips on both sides of the board). It had no problems whatsoever with a low density module with the same exact ratings (memory modules with chips on only one side of the board)... the same capacity, speed, and latency. The low density module was fully recognized, while the high density modules only showed half their specified memory totals. They still worked, and allowed the computer to run, but they just weren't working properly.