laptop not picking up memory

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SteelBlue05

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I have a Compaq Presario 2500 series (laptop). It has 2 memory slots with a 256mb stick of Ram in each slot giving a total of 512mb RAM.

The problem is that only 192 of it is "recognised". If I go into "System" in the Control Panel it says I have only 192MB. It says the same in F2 Setup before I fully boot up. I am pretty sure this is something that only happened in the last few weeks as it was then I started noticing the laptop just getting very slow considering it should have 512Ram.

I know each memory stick and each slot works, I tried booting up on all the different combinations (with 1 memory stick in slot A, then just the other one in Slot B and vice versa). But only ever 192MB is recognised.

Anyone have any ideas as to what the problem might be?
Thanks
 
It could be that 64m is being used by your video card. Some machines share memory this way (instead of using memory onboard the video card) to reduce costs. However, this would have been the case since day one. Is it possible you only noticed it recently, but it has always bee there ? Having said that, 64m would be quite a lot for these purposes - if you have a good card capable of excellent performance then it would normally use its own memory - for performance reasons.

Does it only report a total of 192m even when you have the full 512 in the machine, or is it 192 for one bank and 256 for the other ?

z
 
Hi,
Yes, it only reports 192 even when the 512 is in the machine. It also only reports 192 when either of the 256 sticks are in. When you mentioned the video card you got me thinking. A good while back I was trying to get some game to work (it turned out I didnt have the required video or grahpics card) so I was in BIOS (when you press F2 to get into Set Up before it fully boots up) and I think I set the memory to be used by the video card to be something higer than its default. I cant remember exactly by how much I increased it and I am not 100% sure I reduced it back down to normal now.

Thats probaly it?

Although if I increased it to some high like say 256 would this be taken away from the RAM available to the rest of the laptop? Would it still only report 192RAM. I thought it would report 512 Ram as it shouldnt matter if the RAM is allocated to the video card or whatever.

Thanks for the help.
 
try looking at www.crucial.com. There is a utility there to tell you what memory is compatible with your PC.
Your machine may not support the memory you have inserted or it may only support up to 192 MB. I had a similar issue with a Toshiba laptop in that all it could support was up to 192 MB RAM.

C
 
Reset the dimms, there should be a little slot on the underside of the laptop which you can open up ... take out both of the dimms and re-insert them.

If that doesn't work take one out and run with one, if it picks up 256mb then swap them around and see if it will pick up 256mb when running on the other dimm to see if one of the dimms is faulty

Also you may have to have both dimms the same type of memery or one may not be recognised
 
Capaill said:
try looking at www.crucial.com. There is a utility there to tell you what memory is compatible with your PC.
Your machine may not support the memory you have inserted or it may only support up to 192 MB. I had a similar issue with a Toshiba laptop in that all it could support was up to 192 MB RAM.

C
Click to expand...

I havent changed any hardware on the laptop since I bought it. It came with 512RAM. I checked the manual and it supports up to 1024Ram.

Thanks for the tip though.
 
paddyc said:
Reset the dimms, there should be a little slot on the underside of the laptop which you can open up ... take out both of the dimms and re-insert them.

If that doesn't work take one out and run with one, if it picks up 256mb then swap them around and see if it will pick up 256mb when running on the other dimm to see if one of the dimms is faulty
Click to expand...

Yeah tried all that. I know both work and both slots work as I tried all the different cominations. Thats the first thing I thought might be the problem too.
 
Download and run a hardware interrogation utility like Lavalys Everest Home Edition or CPU-Z and see what it reports. Most likely (as mentioned earlier) your video card is taking 64MB of system RAM (not unusual in laptops). The BIOS and system (Windows) will most likely report 192MB but the utilities above should tell you that you have 2 x 256MB. If this is the case then it's correct and not indicative of any problem.

Sorry - I just re-read your post and I see that it's 192MB even when there is 2x256MB installed. In this case the most likely cause is that the memory you have is not 100% compatible with your laptop and it is only recognising half of each memory stick or only one of them. This can happen due to memory density or rank issues where the system cannot address the full extent of the memory due to low level issues such as chip selects or the actual density of the memory chips used in construction. As mentioned above try one of the memory cofigurators such as Crucial, [broken link removed], Kingston etc. and see what memory is actually 100% compatible with your laptop. If possible try the memory configurator for the manufacturer of your existing and new memory to see if the stuff you have should work.

I've been through the same thing myself and found out the hard way that laptop SO-DIMMs are not all the same and not compatible with all laptops even if they are the right speed and number of pins. I ended up having to buy a second set of memory but managed to flog my redundant stuff to cover my costs and give somebody else a bargain on [broken link removed].

[broken link removed] the Compaq Presario 2500 takes PC2100 SO-DIMMs memory. For what it's worth I happen to have 2 x 256MB Infineon PC2100 SO-DIMMs spare if they would suit and you are interested in buying them from me. :)
 
ClubMan said:
In this case the most likely cause is that the memory you have is not 100% compatible with your laptop and it is only recognising half of each memory stick or only one of them.
Click to expand...

Thanks for the info ClubMan, I think the memory is compatiable as it came with the laptop, I havent changed it since I bought it. I will try out the utilities you suggest tonight. I have a feeling its the graphics\video card.

I also have just bought a 512 stick of memory so must try that out when it arrives.
 
Sorry - I thought that you had recently upgraded. If this just started happening recently then it certainly seems very odd especially if each stick on its own works fine. The video card taking 64MB of system RAM would not be unusual but always seeing 192MB reported regardless of what way the memory sticks are configured seems very odd! It'll be interesting to run those utilities above and see what they report. But more importantly ... anybody else want to buy my 2 x 256MB SO-DIMMs? :D
 
Also try http://www.memtest86.com/ which has a tool I have used previously to check for bad memory. Basically you download either a .ISO image or an application to create a bootable floppy and then boot the machine with the CD/floppy.

One thing worth considering (especially since you have already bought replacement memory) is that it is not worth messing around with doubtful memory. There is little point in being 99.999% sure the memory is good if the .001% chance is correct and manifests itself at a very, very bad time indeed. There is no comfort to be got from the 99.999% in these circumstances.

Since you admit to messing around with the BIOS settings and you reckon that both sets of memmory are good, I reckon your solution might lie in checking back through the BIOS and seeing if you somehow managed to disable one of the banks in the BIOS - that way, no matter what you have in the slot the BIOS will happily ignore it.

z
 
Zag - I also made the mistake of assuming that this was newly acquired memory but it seems to be the original memory that came with the machine and which only recently started exhibiting this problem. The memtest is a good idea though. SteelBlue05 - you mentioned earlier about messing around with the video settings in the BIOS - if this was the AGP aperature setting then you may want to leave well enough alone especially since changing this may have no significant impact (in terms of performance) in many cases. See here (and the articles linked to) for more info.
 
Well its fixed now, the laptop is recognising 504MB RAM (the other 8MB is set to graphics\video card).

Basically I reset the settings in the BIOS to defualt settings and it worked. The problem was when I increased the graphics\video memory allocation in the BIOS to its max (I cant remember what the max was). So Zag and ClubMan were on the right track.

The laptop is booting along now.
Thanks for all the tips and help.
 
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