SDRAM speed compatibility?

AC1

Junior Member
Dec 23, 2002
5
0
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Can anyone please help? I'm trying to figure out if my PC can use 133MHz SDRAM, even though I've currently got 100MHz SDRAM installed. A couple of Staples reps told me that I couldn't use the 133MHz SDRAM at all due to my motherboard, but a couple of websites I've seen (like Crucial.com) indicate that the 133MHz is backward-compatible, and will just run slower than their rated speed but still work. Anyone know which is correct? Please help!

My computer's a Dell L933r, BTW.

Thanks so much.
 

hdeck

Lifer
Sep 26, 2002
14,530
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crucial is correct. staples just wants you to pay for the now more expensive pc100.
 

Kingofcomputer

Diamond Member
Apr 6, 2000
4,917
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50/50.

It could be your old system's motherboard chipset doesn't support 256Mbit or 128Mbit chips.

256MB dimm uses 16 x 128Mbit chips or 8 x 256Mbit,
128MB dimm uses 16 x 64Mbit chips or 8 x 128Mbit chips,
etc.

In PC100 age, people bought 128MB dimm most.
Later in PC133 age, people bought 256MB dimm most.

The Staples reps could know this, so he/she suggested you to get old smaller size PC100 to avoid newer bigger size PC133 not working with your old system.
 

bozo1

Diamond Member
May 21, 2001
6,364
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PC133 will work. The question is will the modules you are looking at work. If they are 256M modules with chips only on one side the answer is no if your motherboard uses an Intel chipset.

 

AC1

Junior Member
Dec 23, 2002
5
0
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thanks for everyone's help, but unfortunately it looks like there's a difference of opinion(?!!)
when I use crucial.com's memory selector (inputting my Dell L933r system), it presents me with both 133 & 100MHz memory. so that leads me to believe that both are usable, especially since crucial's got a compatibility guarantee. but just now i used dell's own memory selector, and it only comes up with 100MHz memory. ugh. anyone have experience with this problem directly? is this an uncommon problem?
 

thorin

Diamond Member
Oct 9, 1999
7,573
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There's a simple solution (without us having to explain all the possible out comes and variations on memory production/technology), purchase it somewhere you can return it, try it, if it works then great, it not then return it.

Thorin
 

Kalvin00

Lifer
Jan 11, 2003
12,705
4
81
I have an Intel CA810 mobo. I bought 256 MB PC133 down at CompUSA a while ago. The memory in here is PC100. Turn on the comp with the new ram, get a beep code. It means 'Parity cannot be reset.' I look at the online mobo documentation, it can't support pc133, only 100. I'm never purchasing another item with Intel written anywhere on it, hehe.
 

bozo1

Diamond Member
May 21, 2001
6,364
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The problem is not PC100 vs PC133. It's whether the motherboard can support so called 'high density' RAM. Crucial shows PC133 being compatible because it is and their PC133 memory is not 'high density'. The cheaper modules being sold by Staples, CompUsa, etc., are and that's the problem.
 

billyjak

Platinum Member
Oct 9, 1999
2,869
1
81
Be aware that some pc 133 is not backword compatible.
They are correct in telling you this, Crucials memory is backwords compatable so you can mix it with theirs.
 

RickH

Senior member
Aug 5, 2000
784
0
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Listen to the Bozo. It's not the speed, it's the density. Just buy the ram from Crucial, it will work, and you don't have to mess with rebates. RRRRR