RAM not recognized

December 17, 2011 at 16:39:20
Specs: Windows XP SP3, P4 3GHz HT/512 MB RAM
I added a 1GB DDR 400 SDRAM PC3200. When I installed it it wouldn't boot up at all. It just shows a blank screen. However when I removed the 1GB module, the machine successfully booted into Windows XP. And yes, the RAM is compatible (with my IBM ThinkCentre M51). The system can support up to 4GB of RAM with 1GB per slot maximum. It's either a defective stick or it isn't running in dual channel mode.

Here is the configuration with the 1GB stick:
Slot 1: empty
Slot 2: DDR 400 SDRAM PC3200 256MB (paired with slot 4)
Slot 3: DDR 400 SDRAM PC3200 1GB
Slot 4: DDR 400 SDRAM PC3200 256MB (paired with slot 2)


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#1
December 17, 2011 at 17:49:16
"It's either a defective stick or it isn't running in dual channel mode"

Dual channel mode has nothing to do with it. Temporarily remove all the RAM & try the new stick all by itself. And make sure it's fully seated in it's slot & clipped in place.


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#2
December 17, 2011 at 18:51:30
For dual channel to work you must install in pairs. 3 sticks runs in single channel mode only. You may need to refer to your motherboard manual to verify what ram is compatible and in what configuration. or visit www.crucial.com and let them scan your system.

Goin' Fishin' (Some day)


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#3
December 17, 2011 at 20:28:04
"IBM ThinkCentre M51"

That's not enough info.
There are many different M51 machine types, and only some of them have 4 ram slots - e.g 8146 .


Find your specific Product number and machine type and tell us what they are.

Finding my product number
http://support.lenovo.com/en_US/Fin...
....

"I added a 1GB DDR 400 SDRAM PC3200. When I installed it it wouldn't boot up at all. It just shows a blank screen. However when I removed the 1GB module, the machine successfully booted into Windows XP."

That's exactly what happens when the memory module is incompatible with using it in the mboard.....
- when it is installed by itself
- or - it works when installed by itself but it does not work when it is installed in combination with other ram modules it isn't compatible with being used with.

Ram that works in another mboard , or any ram you buy or have lying around, may not work properly, or sometimes, not at all - even if it physically fits and is the right overall type (e.g. SDram, DDR, DDR2, etc.; PCxxxx, xxx mhz) for your mboard. In the worst cases of incompatibilty your mboard WILL NOT BOOT all the way with it installed, and the mboard may not even beep - the ram has to be compatible with the mboard's main chipset, or in the case of recent mboards, compatible with the memory controller built into the cpu.

See response 5 in this for some info about ram compatibilty, and some places where you can find out what will work in your mboard for sure:
http://www.computing.net/hardware/w...
Correction to that:
Mushkin www.mushkin.com

Once you know which module ID strings (part numbers) work in your mboard, you can get them from anywhere you like that has ram with those ID strings.

If you have brand name ram, it is usually easy to look up whether it's ID string (part number) is in a list of compatible modules found by using your mboard or brand name system model number.
If the ram is generic, that may be difficult or impossible.


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#4
December 18, 2011 at 06:51:27
They are boards that are capable of running dual channel with 3 sticks of memory. My old p4 board is caple of running dual channel with two different memory sticks.

You know the real meaning of peace only if you have been through the war.


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#5
December 19, 2011 at 10:48:36
"They..." (supposed to be There ?) "...are boards that are capable of running dual channel with 3 sticks of memory. My old p4 board is caple of running dual channel with two different memory sticks."

Apparently 3 modules can run in dual channel mode in specific circumstances, but not in others.

E.g. see this...

Desktop Boards
Single, dual, triple, and flex memory modes
http://www.intel.com/support/mother...

Pairs of modules must be the same size and be installed in specific slots for them to run in dual channel mode, but they don't have to be identical modules as long as the memory organization on the modules is the same.
Buying them in matched sets that are identical modules is merely a convenient way to be assured the pair will run in dual channel mode.

E.g. see the info in this....

Multi-channel memory architecture
http://en.wikipedia.org/wiki/Multi-...
.........

You can confirm whether your ram is running in dual channel or triple channel mode,
e.g. by using CPU-Z

CPU-Z
http://www.cpuid.com/softwares/cpu-...

This page shows that.....

http://www.cpuid.com/medias/images/...
........

In any case, the benefit of running ram in dual channel mode is a lot less than it is in theory.

E.g.

What does Dual Channel mode mean, and do I need it?
http://www.ramcity.co.nz/what-does-...

Excerpt:

Based on our own experience, dual channel mode provides about a 5-10% increase in performance in most games and applications.
.........

Dual channel mode is a capabilty of the mboard for DDR, DDR2, or DDR3 ram, not the ram modules themselves.
The mboard must support dual channel mode, or triple channel / dual channel mode (two DDR3 modules can run in dual channel mode) - some earlier DDR and DDR2 mboards DO NOT support dual channel mode

Crucial lists these machine types for ThinkCentre M51:
8095, 8096, 8097;
8104, 8106, 8108, 8118, 8120, 8141, 8142, 8143, 8144, 8145, 8146,

User Guide
(machine) Types 8097, 8143, 8144, 8146; 8422, 8423, 8427
http://download.lenovo.com/ibmdl/pu...

Search for: channel - the mboard does support dual channel mode.

Memory installation info - pages 28 and 29 of the *.pdf

Manual covers both DDR and DDR2 ram mboards - all of the machine types have 4 ram slots.
...

Crucial lists these machine types for ThinkCentre M51e - 9213.

I looked at the User Guide that are for machine types that includes that machine type - the mboard has 4 ram slots but it has NO information in it that says it supports dual channel mode.


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#6
December 24, 2011 at 19:26:53
Thanks for the help but it was actually a defective stick. Bought a new one and it worked perfectly.

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