Problem with new memory in old laptop

deefadog

Hi all, i have a Dell Latitude C640 (Old i know) it only had 256MB in it so i bought a 512mb module for it. Now new memory works ok on it's own but not with the 256mb. Do these have to be installed in equal pairs?

Here is the DELL support page (but there is no mention of pairs) - http://support.dell.com/support/edocs/systems/latc640/sm_en/upgrades.htm#999869

Thanks for any help

btw i got this memory for it - http://www.play.com/PC/PCs/4-/931239/Computer-Memory-512MB-PC2700-DDR-333Mhz-200pin-SODIMM/ProductReviews.html

dogmaryxx

http://www.crucial.com/uk/store/listparts.aspx?model=Latitude%20C640%20Series

macman

No logic to this, but have you tried swapping them to the opposite slots?

aliEnRIK

Older computers do tend to require matching pairs

macman

Not according to Crucial for that model though. I know they're not infallible, but rare to catch them out.

deefadog

Thanks for the info forgot about crucial!

The one i bought was 2700 and the 256mb is 2100, but it does say -

No, you can install modules one at a time, and you can mix different densities of modules in your computer. But if your computer supports dual-channel memory configurations, you should install in identical pairs (preferably in kits) for optimal performance.

Does the 2700 & 2100 refer to the density?

spud17

I've mixed 2100 and 2700 on a desktop without problems,(2700 was much cheaper), but machines can have minds of their own.
I'd try macmans suggestion first.
Funny I was going to buy that memory from Play.

Richie-from-the-Boro

Put the lower speed 2100 in slot 0 & the 2700 in slot 1, the puter will read the first bar as the speed standard and the second bar will [ step down to ] perform at the same speed as the first bar.

macman says: "" have you tried swapping them to the opposite slots? ""

- did you try his suggestion ?
- I don't know if the Intel 915 MOBO needs matched pairs
- one painful solution is to buy a-n-other exact same 512 bar and replace the 256

deefadog

I am at work at the moment, so can't test. But yesterday the 256 (2100) was in slot 1 and the 512 (2700) in slot 2 and that just hung at the bios screen. Same as with 512 (2700) on it's own in slot 2 (But i can see why that would not work )

I don't think i tried the 512 (2700) in slot 1 and 256 (2100) in slot 2, i'll give that a go, but as you say £12.99 is not to painfull to get another one and i have return stuff to play in the past with no hassle!

Maybe slot 2 is damaged in someway as it's probablly not been used ever, so i may try and insert the memory a few times, incase there is a build up of residue on the pins!

Thanks for you help guyz, much appreciated :T

Richie-from-the-Boro

I am at work at the moment, so can't test. But yesterday the 256 (2100) was in slot 1 and the 512 (2700) in slot 2 and that just hung at the bios screen. Same as with 512 (2700) on it's own in slot 2 (But i can see why that would not work )

- I can't see why the slower in 0 and the higher speed in 1 doesn't work, the higher is capable of 0 but the lower is not capable of 1 ? , I don't get that !

- I too can see why either bar in slot 1 won't work at all, simply because slot 0 must be populated first

I don't think i tried the 512 (2700) in slot 1 and 256 (2100) in slot 2, i'll give that a go, but as you say £12.99 is not to painfull to get another one and i have return stuff to play in the past with no hassle!

- everything holds risks but for £13 I'd buy a-n-other identical 512 module and see if the BIOS will handle it

Maybe slot 2 is damaged in someway as it's probablly not been used ever, so i may try and insert the memory a few times, incase there is a build up of residue on the pins!

- old fashioned school rubber is good for cleaning pins on SODIMM or any DIMM's / video card teeth etc

spud17

Maybe slot 2 is damaged in someway as it's probablly not been used ever, so i may try and insert the memory a few times, incase there is a build up of residue on the pins!

Good point, I once tried to fit an AGP card in an old PC with failed on-board graphics.

It wouldn't work at all.

The slot was full of dust and crud, a good spray with Servisol switch cleaner sorted it.

I am not suggesting anyone tries the above.