My computer does not start after installing a new memory modules and does not recognize the correct amount of RAM.
In case you bought a new memory for your computer, installed it and the computer won’t boot anymore you don’t have too many options.
The most important first step to resolve this problem is to check whether all RAM modules are properly placed. Booths sides of each memory module must click and fit perfectly into the DIMM slot.
Alternatively, if the problem persists and your PC does not boot, you need to reset the BIOS. Make sure the jumper is set to the reset position, and then remove the battery for at least 15 seconds. It is possible that values from the old memory are still stored in your BIOS, preventing it from booting properly.
If the problem persists, you probably have a defective module or the kit you bought is not supported by the motherboard.
To diagnose a non functioning module further – test each RAM stick individually to find the defective one. Remove one of the sticks and leave the other (on the main memory slot; check the MB manual), restart the PC, if nothing happens the module is faulty.
However, if one of the modules works, test it on all remaining slots to rule out DIMM slot issues.
My computer does not recognize the correct amount of memory
There are a few situations where your system may recognize less RAM than it actually has.
Here are some of the problems and their corresponding solution.
Unsupported amount/type of RAM
The memory module type/brand or the amount you just installed is not supported by the motherboard.
Check your motherboard manual for how much RAM you can use with each DIMM slot, and make sure your motherboard supports the RAM you use.
Search online for your motherboard model and RAM compatibility list for specific serial numbers.
For example an OEM model like Dell OptiPlex 5060 MT supports a maximum of 64 GB of RAM on 4 DIMM slots. Meaning the maximum memory supported per slot is 16 GB.
While other motherboards from the same period, like ASRock B360 Pro4, support a maximum of 128 GB RAM with 32 GB per slot.
There is another issue in this section and that is the OS type. If you use 32 bit Windows the maximum amount your system will detect is 4GB.
There is no such limitation with 64-bit Windows and 64-bit CPU.
The RAM module was not installed properly
When the module is not properly placed or there is a poor connection between the pins inside the slot and module, the system may not recognize it or not boot at all. The RAM module must be properly seated into the slot and both clips must be clicked during install.
There is a faulty memory module
Faulty memory modules will not be recognized by the system or will be recognized as the wrong amount. Test each stick individually to find the defective one. Use your motherboard main memory slot to test.
At the end if the stick is defective, you should return the whole kit and not just the problematic stick.
The next two scenarios are harder to diagnose, because you don’t always have a spare CPU or motherboard for a swap.
But there are some prophylactic moves you can do.
There is an issue with the CPU
CPU problems may sometimes manifest as memory errors. For example bend pins can cause wrong memory amounts.
Take out the CPU and check for bend pins, apply thermal paste, reseat the CPU, place the cooler (without any excess pressure and good surface contact), and turn the system back on.
Busted DIMM slots or dead channels
Busted slots or dead channels can cause issues like this one. If you have a working RAM kit try different combinations of slots and modules to diagnose the problem.
And at the end, if the system finally boots and the memory amount is as you expected, it is a good idea to run couple of Memtest86+ passes to be on the safe side.