Mixing RAM (Brand/CAS)

Posted on 2005-03-18
Medium Priority
Last Modified: 2010-04-26
I know "Can I mix ram speeds?" is a common question, but mine is more towards mixing the same speed of ram but with different CAS values. I have 2 sticks of 512 MB Corsair PC2700 CAS2 currently installed on my Abit BH-7 motherboard and it works fine. I recently bought a cheap stick of 512 MB Crucial PC2700 ram but forgot about the CAS... Frankly i dont even know what CAS is, just that a lower number is better. The Crucial ram i bought is CAS 2.5.

Anyways, my computer would re-boot by itself at random times with all 3 sticks installed, so I went into the BIOS and changed my CAS speed to 2.5 instead of 2. It no longer re-boots (so far) but when i go to my computer's properties it says I only have 1.00 GB installed, when I should have 1.5 GB installed. Is this just windows not displaying my total ram properly, or is only 1.0 GB of it working? When I restart my computer, it says i have 1.5 GB during bootup, so im inclinded to think it is just windows... but I'd like to know for sure, or if theres anything I am doing wrong.

Question by:j_gordon
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Expert Comment

ID: 13581009
If the BIOS sees it, it is probably a Windows thing.

If you want to know more about the numbers, this is a good start:

Accepted Solution

stockhes earned 2000 total points
ID: 13581271
From this link:

chapter 1-1 features and specifications



supports 3 DIMM DDR 200/266(max 2GB)
supports 2 DIMM DDR 333(max 2GB)

----snip end ----

MAybe you are on the edge with that third stick ?


Expert Comment

ID: 13582204
Hi there.

This is not a good idea of doing so.

Imagine you're putting two V6 engine and a normal engine together.

To make them able to run together at the same limit, you tune the V6 down to normal engine power. Do you think this is the practical way? :-)


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