RAM DIMM compatibility with mother board

Asus Laptop with intel pentium processor...
April 6, 2020 at 02:16:20
Specs: Windows Vista, 2GB

I asked the following question in another forum, but they did not gave me a really definitive answer.

Someone told me in that forum DDR can be picky some times and that means he cannot tell in advance for sure whether this EBAY RAM DDR2 DIMM is compatible with my desktop computer's motherboard. May be any of you can provide a more definitive tip to let me know whether these EBAY RAM DDR2 DIMMs will work on my motherboard or not:

"I would like to ask you whether the 2 RAM modules I found on eBay, "2GB 1GB DDR2 PC2-6400U 800MHz 1.8V NON-ECC Computer RAM Memoria escritorio SP",


are compatible with this mother board, G31T-M2 or not. This mother board has two ram slots and I can read "DDR2 800" besides one of the slots.

This computer currently has 2 old 1GB modules with a white sticker with this text, "HYS64T128020EU-3S-B2 Y1E73408 ASSEMBLED IN MALAYSIA 1GB 2Rx8 PC2-5300U-555-12-E0", on each slot . I have counted the number of pins of each module and this number is 120.

I wanted to upgrade them, by replacing each one with the 2 GB module I found on eBay and to increase by doing so the total RAM memory from 2Gb to 4 Gb.

Thanks in advance"

message edited by thosecars82

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April 6, 2020 at 05:13:44
Start by going to the motherboard website: https://www.ecs.com.tw/ECSWebSite/P...

The board supports:
- Dual-channel DDR2 memory architecture
- 2 x 240-pin DDR2 DIMM socket support up to 4 GB
- Support DDR2 800/667 DDR SDRAM

The RAM speed you need is determined by the CPU's FSB speed. For best performance, the CPU/RAM frequency ratio should be either 1:1 or 1:2. Which means:
1333MHz FSB = 333MHz freq = DDR2-667 RAM (1:1)
1066MHz FSB = 266MHz freq = DDR2-1066 (1:2) or DDR2-533 (1:1)
800MHz FSB = 200MHz freq = DDR2-800 (1:2)

As for the eBay link you posted. Obviously not in English but why are you buying from eBay in the 1st place? None of us can tell you with 100% certainty it will work. The description is odd - "2GB 1GB DDR2 PC2-6400U 800MHz" - why does it say "2GB 1GB"? It appears to be 2GB but if they can't write their ad correctly, can the seller be trusted? My suggestion is to find a more reputable vendor & get brand name RAM, not generic.

Also, I noticed in your specs your listed Vista as your OS? It's an accident waiting to happen.

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April 6, 2020 at 05:15:52
Motherboard G31T manual - https://data2.manualslib.com/pdf3/6...

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April 6, 2020 at 09:05:45
Thanks a lot for the advice!

1. With reference to "The RAM speed you need is determined by the CPU's FSB speed", does the FSB speed need to get updated to 800 Mhz manually by me in case I try to upgrade the RAM memory with the 800 Mhz Ram modules I found in the ebay link?

2. With reference to " why does it say "2GB 1GB"?", the reason is that they are selling both the 1GB Ram module and the 2GB Ram module. There is a toggle in the ebay page to choose the one you want to buy.

3. With reference to "Also, I noticed in your specs your listed Vista as your OS?", well, I wrote Windows Vista because this OS was the original computer OS and it is indeed still installed in the computer. But the OS that gets used in this computer nowadays is Lubuntu. Windows Vista is NOT used any more even though it is still installed.

4. With reference to the manual I found at https://es.scribd.com/document/3407...

I read the G31 chipset Nort Bridge "Supports 512 MB and 1 GB DDR2 DRAM technologiesfor x8 - and x16 devices"

Nonetheless in the Memory section it is possible to read "Holds up to 2GB per DIMM with maximum memory size up to 4GB."

Therefore I still wonder whether the maximum RAM DIMM size allowed for each of the motherboard's 2 ram slots is 1GB DIMM or 2GB DIMM.

Thanks again.

message edited by thosecars82

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April 6, 2020 at 09:57:43
Frequencies are what you should be using when pairing up RAM with CPUs. Don't confuse FSB speeds or DDR2 speeds with frequency. For Core 2 Duo CPUs, the frequency is FSB/4. For DDR2 RAM, the frequency is rated speed/2.

In other words, a 1333MHz FSB CPU runs at 333MHz frequency (1333/4).
And DDR2-667 RAM runs at 333MHz frequency (667/2).
They are a perfect match.

If you pair up DDR2-800 RAM (400Mhz freq) with a 1333Mhz FSB CPU (333MHz freq), the frequencies won't match, so the performance will be less than ideal. The system will still run & you probably won't notice much difference, if any, but 1:1 matching (or 1:2) is what you should shoot for.

If you get DDR2-800 RAM & your board allows overclocking, you should raise the CPU FSB to 1600MHz & lower the CPU multiplier to keep the CPU reasonably close to it's original speed. For instance, say you have a CPU that's supposed to run at 2.0GHz at 800MHz FSB (10 x 200MHz). You could leave it as-is, pair it up with DDR2-800 & maintain a 1:2 ratio, but it would be much better to change the CPU settings to 5 x 400MHz (1600MHz FSB) & run a 1:1 ratio. The CPU would still run at 2.0GHz, but the FSB speed would be twice as fast.

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April 7, 2020 at 02:49:36

After checking the BIOS settings of my motherboard:
- I see the CPU frequency is 266 Mhz and it seems this setting cannot be updated manually through out the BIOS itself.
- I also see another setting in the BIOS for setting up the DRAM speed. It has 3 options: Auto,
667 Mhz and 800 Mhz.
- I do not see any BIOS settings to be able t manually update the FSB frequency. I only see a mention under the Thermal management (enabled/disabled) settings of the BIOS that says "For the processor its CPUID belows 0F41h. TM2 only can be enable under below setting:
1. Freq .>=3.6GHz FSB800
2. Freq .>=2.8GHz FSB533"
- it seems the BIOS does NOT allow me to change the CPU frequency to 400 Mhz to achieve 1600 Mhz FSB/4 = CPU frequency and 1600 Mhz FSB/2 = RAM frequency,

Would you suggest I should better look for buying 667MHz DDR2-RAM?

In that case according to the FSB frequency/4 rule I should overclock the CPU from 266 Mhz to 333 Mhz. Anyway the BIOS does not allow me to change that either.

I have also found these 667 Mhz 2GB DDR2 DIMM: 2GB PC2-5300U 667Mhz KVR667D2N5/2G Desktop RAM DDR2 Para Kingston ZT SP

Do you think the 667 Mhz RAM DIMM of the following link will work better than the 800 Mhz RAM DIMM of the link I posted in a previous comment?


Thanks in advance

message edited by thosecars82

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April 7, 2020 at 03:08:14
My CPU is Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz in case that helps.

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April 7, 2020 at 05:40:33
I personally go with the 800MHz RAM. While it is not optimal with your locked settings it is still faster and you can always underclock the memory if you still want to achieve the optimal ratio.
Understand that for most boards what you have verified already does indicate that this memory SHOULD work but there is always a small chance that if the memory is not on the boards RAM Compatibility list specifically (meaning they tested it already) that there may be an issue running it. But it should work.

You have to be a little bit crazy to keep you from going insane.

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April 9, 2020 at 02:12:14
Thanks for your support a lot to all of you! I ended up ordering the 800 Mhz RAM memory of the Ebay link as an experiment.

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