My Lenovo ThinkStation S20 e D20 is having 24 GB memory but only 16 GB is usable

[Carry On!]

I have bought some additional memory for the Lenovo ThinkStation D20 and now I am having total of 24.0 GB. This is installed as 6 modules of 4 GB memory and that makes it total of 24 GB. I have purchased them all from the Lenovo. I found that they all are getting detected properly without any problem but when I check the total memory then it says that this is just 16 GB. This msounds weird to me and so I am looking for some solution for this. Ca n somebody over here tell me that what is the problem with this and how can I solve this issue. If you have something that can be helpful for me then please let me know that. I will be thankful for all the replies.

[Wisaal]

I think that some of the memory modules are not seated properly in that and this is the reason that you are getting just 16 GB out of 24 GB. So this is the first thing that needs to make sure. Remove all the modules and try by inserting then one by one and see that which module is having problem. This is one of the most possible reasons for this issue and trying them one by one will solve the problem for you. So do this and see if this helps you and if this is not the problem, then reply us back and we will try to get this solve in some other possible ways.

[Carry On!]

In the cases like this, some of the times, re flashing the BIOS solves the problem and so you can also try with the same. Earlier, I was having total 6 GB RAM but that was showing me 4 GB. I did the same and this solved the issue for me. I hope that it will do the same for you as well.

[Wisaal]

Make sure that all the six memory modules that you are using is of the same type. I mean that there must not be any difference in the modules. If there is any difference in any of the property of the module then you might face the issues like this. There are some of the other possible reasons for this that can cause this problem but this is the first thing to be checked. It is recommended to use less memory module, I mean instead of using smaller units it is better to use a large unit. I have seen that there are many of the issues with the memory while using many memory modules. Anyways, first verify that all the modules are with the same specification.

[Carry On!]

There is no need to remove all the modules from it to check. If at the system start, you are getting some beep noise then this can be problem with the memory module otherwise this is problem with something else, may be operating system.

[Wisaal]

I would like to tell you that you will never get the complete memory to use. BIOS also require some memory to work and because of this the operating system reports lower memory than what you are having in the system. OK , now question arises that how much this reduce the memory, so this is depend on how well the codes are written.

The best way for you is to check that if BIOS is reporting all the memory installed then you cannot do anything. It will handle the memory in its own way. If you are getting that total number of RAM in the BIOS is less than what you are actually having then it will be better for you to go for the reseating route.

[Carry On!]

Which CPU are you using? Is it 5500 or 5600 series xeon. If you are using the 55xx then there is possibility that this is something related to the xeons handle memory ranks. Other than this, you have also not mentioned that whether you are using the dual- or single-ranked or mixed memory.

[Sudhamay]

If there is problem with any of the memory slot the also you will have the same problem. So connect only one RAM stick in one slot and see if that slot is working or not. Do this for the other entire remaining slot and make sure that all the slots are working. If there is problem with the RAM slot then it will not provide proper connection and as a result of that you will get less memory.

[Kirt]

There are some of the threads on this forums discussing about the same. So it will be better for you to look at the replies over there and see if any of the reply from them seems to be useful for you. Here are the links for those threads:

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