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78855
December 24th, 2010 17:00
Optiplex 755 - Additional 2GB Memory Not Recognized
My Optiplex 755 was delivered with 2GB memory (2 x 1GB, non-ECC, 667MHz, DDR2 SDRAM), and two empty slots. I ordered and installed an additional Dell-branded 2GB memory (1 x 2GB, non-ECC, 800MHz, DDR2 SDRAM). The memory stick was installed in location #3. Unfortunately, the BIOS does not recognize the new memory stick.
The memory I ordered (SNPYG410C/2G, Dell Part #A4062633) is the top item listed as the Dell-approved memory upgrade for my Service Tag. I understand that the new memory will only operate at 667MKHz, but that will not be an issue, as long as the system sees and accepts the new memory. Furthermore, I understand that Win7 32bit may only recognize an additional 1GB rather than all 2GB.
Does anyone have a suggestion?
RoHe
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December 24th, 2010 18:00
Normally, you're supposed to install DDR2 memory as matched pairs. Otherwise the system won't take advantage of the extra speed of DDR2. So you would have been better off ordering 2x 1GB modules. And that could be part of your problem now.
Are you sure you installed the new module correctly? Did it click into place when you gently pushed down on it from the top?
Try this...Power off and unplug . Press/hold power button on the tower for ~15 sec. Open the case and remove both old modules. Install the new module in slot 1. Now remove the motherboard battery and press/hold power button again for ~30 sec. Reinstall the battery (right-side-up!) and see if it boots with the one module. If not, it might be a bum module.
If it works with just the new one, power off etc and move the new module to slot 3 and put the other two in slots 1 and 2. Do the "battery thing" again and see if it recognizes the new module now. If not, you may have a slot failure or it won't recognize the module because you didn't install a matched pair.
Ron
Hytec
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December 24th, 2010 18:00
Ron, thanks for your reply. Yes, the 2GB module "clicked" into the #3 slot with no problem, and the clips closed easily without any force needed. I will attempt your slot swapping sequence tomorrow after a good night's sleep.
I seem to remember from many years ago that the motherboard would lose much, if not all its basic settings by removing the CMOS battery. Unfortunately, I don't remember any details. Can you refresh my memory?
If you are correct about the Optiplex needing two "matched" 1GB modules instead of a single 2GB module, and you probably are, then I am very upset that Dell would even offer the 2GB module as the topmost recommended upgrade on their list.
Hytec
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December 25th, 2010 07:00
Ron, thank you for your advice, all is fine now.
The system recognizes the 2GB module when plugged into DIMM-1, and it recognizes the two original 1GB modules now plugged into DIMM-3 & DIMM-4.
It's unfortunate that this configuration, apparently required when adding a 2GB module, was not included with the text describing the 2GB module and/or with the pamphlet included in the module package. Hopefully a Desktop Forum administrator or a Dell employee monitoring this Forum will pass the word upward to have the sales and/or installation text modified to include this requirement and save future memory purchasers the minor aggravation that I experienced.
Thanks again for your help, and Merry Christmas!
RoHe
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December 26th, 2010 12:00
Glad that got it sorted out.
But keep in mind that the system is probably not taking advantage of DDR2 RAM's extra speed since there's no matching module in slot 2.
As for Dell changing the info packet, forget about it..! :emotion-5:
Ron
RoHe
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December 26th, 2010 12:00
Me again...
BIOS resets to factory default settings whenever you remove the motheboard battery. That forces BIOS to go examine all the installed hardware again, and sometimes that's necessary to make it recognize something new. For the most part, you probably are using default settings, so it wouldn't make much/any difference to you.
If you don't have an internal floppy drive, BIOS would default to turning on the floppy drive controller so you'd get a floppy drive error on booting until you turned the controller off again, but that's minor and there's no harm done.
Ron