Question about OLD SDRAM memory

[kaos kid]

I recently inherited an HP computer with a P4B-MX board that uses up to 3x1GB 168-pin SDRAM. It had one 256mb stick of memory, labeled as HP brand 1818-1851. When I tried to add an additional 256mb stick of SDRAM I had, it wouldn't play nice with it. What I did notice was that the HP stick is larger than all the other SDRAM modules that I have (taller? definitely a different size although the pin layout is the same). Is this a different kind of memory, or just HP being proprietary? When I took out the HP brand memory stick and put in 2 256mb sticks of my own SDRAM, the computer works fine and installed XP with no problem. What is it about this HP stick that makes it different?

Thanks

 

[jjmIII]

Sometimes a mobo just doesn't like certain sticks together. Taller, bigger (physical size) sticks are usually just older sticks with less density and the memory chips just need more space.

Old low density sticks are needed in some old mobos that can't run single sided, or high density memory.

 

[kaos kid]

Thanks for the quick reply! I guess I'll just put that odd memory stick in the drawer unless I really need it.

 

[Blain]

Taller, bigger (physical size) sticks are usually just older sticks with less density and the memory chips just need more space.

:\ Wrong...
Physical size has nothing to do with "low density", it's just the way the manufacturer chose to build the module, and/or the type of chips used (BGA or TSOP).

The older HP may have limitations on DIMMs used together in certain slots.
Check the manual for the PC to find out possible DIMM slot memory configurations.

 

[kaos kid]

Perhaps that is possible. I think I read online that it has a limitation that says it can use 3 sticks of PC100, but only 2 sticks of PC133. Like I said previously, I just took that stick out and replaced it with 2x256MB of some other (smaller, normal size) PC133 I had and it boots fine. I'll just keep that odd stick for if I ever sell the box then I'll put that one back in.

 

[Blain]

Sometimes the limitations have to do with the DIMMs being single or double sided and specifically which slots they are installed in.
The manual for the MB should tell you exactly what combinations will work.

 

[kaos kid]

And it appears it depends on the board's origin and OEM use. The ASUS version manual allows 3x1GB. Since I have the HP version (narrowed it down to the Vectra VL420) its manual states 3x512MB only. When I go to crucial memory finder, it states that the max memory is 3GB, but then it has an asterisk that states 3x512mb "*Not to exceed manufacturer supported memory." so I'm thinking the limitation is in HPs bios, not the boards' hardware.

One thing I can't seem to find out from the HP manual (without taking off hsf) is what the fsb is for this system. I would think it is 400fsb, but since it uses PC133 I wonder if it is a 533fsb cpu and board. Any ideas about that?

 

[Blain]

If your HP is a Vectra VL420...
"There are three 168-pin DIMM slots on the system board for installing main DIMM slots memory. You can install 133MHz SDRAM modules, these are available in 64, 128, 256 and 512MB memory modules. 32MB memory modules are not supported.
You can install a maximum of 1.5GB (3 x 512MB modules).
You can only use non-ECC memory modules."

 

[kaos kid]

What I meant was maximum 512MB each slot, I should have clarified. I know that 256MB works, it came with one and I currently have 2x256MB in there now. Not that it matters, I think for a system this old 1.5GB is more than enough. I'll probably just run it with 3x256MB anyway once I get it all set up for my kids.

 

[jjmIII]

:\ Wrong...

Where the middle finger icon?

I guess I wasn't right, but I always see old low density ram in those "bigger" form factors.

 

[kaos kid]

Thanks to both of you for your help, 2 heads are better than one!

 

[Blain]

Where the middle finger icon?

It was simply wrong, not heresy.

 

[Blain]

Thanks to both of you for your help, 2 heads are better than one!

Very True

 

[Denithor]

One thing I can't seem to find out from the HP manual (without taking off hsf) is what the fsb is for this system. I would think it is 400fsb, but since it uses PC133 I wonder if it is a 533fsb cpu and board. Any ideas about that?

Just download & run CPU-Z. That will give you more details about your system than you need.

 

[kaos kid]

CPU-Z? D'oh! I'm such an idiot not to think of that since I already have it installed on the desktop I'm currently using. I only sporadically mess around with my computers, so I tend to forget the handy stuff I used earlier. CPU-Z shows that the processor in there is a skt 478 400fsb Williamette. The darned HP manual for it doesn't say if it is compatible with 533fsb cpus (I hope so since it uses PC133), I guess I'll have to test that one out the hard way. Thanks all for the replies!