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General discussion

motherboard

Feb 25, 2004 1:27PM PST

i have a motherboard that supports both pc 133+ pc 100
memory....the question is can you use both types together....i have 256 mb of pc 133 and i have another stick of pc 100...any help would be appreciated...myk

Discussion is locked

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Re:motherboard
Feb 25, 2004 1:50PM PST

If it works, I believe your 133 will "clock down". What OS? I don't think you'll see a difference between 256 and 512 on 9x or Me. XP....slight.

Your choice!

~Tom

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Re:Re:motherboard
Feb 26, 2004 5:37AM PST

Thanks...I was told that XP eats up a lot of memory and runs best with at least 512 MB of Ram...is that not true?

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Re:motherboard + 256M memory stick = Beware the BX issue.
Feb 25, 2004 8:57PM PST

Let me make some statements and see if it clears it up.

1. BX chipsets have issues with generic 256M SDRAM modules you get at the grocery store. The SHORT explanation is that the BX memory controller only sends so many address lines to the memory slots and uses 2 CAS lines to get both sides (hence Double-sided!) of the memory stick working. If you have a BX chipset and the 256M stick reads 128M, you have the wrong memory stick type.

2. If what's in the machine is PC100, then PC133 works fine 99.99% of the time given item #1

3. If what's in the machine is PC133, then PC100 is not a good idea without research about the CPU, FSB and more.

Bob

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Re:Re:motherboard + 256M memory stick = Beware the BX issue.
Feb 26, 2004 5:35AM PST

Thanks...I have an FIC AZ11ea motherboard, an amd athlon 1.4gig processor and an office depot on sale for 25 bucks pc-133 256 MB stick of ram in the machine now...It does say in my manual that the FSB and DRAM can be asynchronous...but i don't even know if that means...anyway i appreciate the help i've looked all over the FIC site.

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I know the AZ11, There won't be an issue. Go for it.
Feb 26, 2004 7:39AM PST

In the future, supply that info early in your post.

Bob

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Two definitions
Feb 26, 2004 6:00AM PST

1. SDRAM [also DDR SDRAM] is "Synchronous Data" memory which means that it runs in synchronism with the memory bus clock. Thus a higher speed rating memory will run at the memory bus speed. For the PC 100 to run your memory bus will have to run at 100 MHz. THEREFORE the PC 133 will run at only 100MHz.

The asynchronous comes into play when one considers the memory bus [memory to the Northbridge part of the chipset, Intel calls it MCH, Memory Controller Hub] and then the FSB from the Northbridge to the CPU.

If the two busses are not processing data in synchronism, the operation is lossy in that the Northbridge has to introduce wait states to ensure that the data transfers don't get fouled up. Always best [faster] to use memory that allows the Northbridge to work synchronously.