7 Replies Latest reply on Aug 3, 2011 1:28 PM by Jose_Intel

    DP55WG error 21 won't boot


      It is apparent that Corsair memory is not compatible with the DP55WG motherboard. I was getting a 21 error and no beeps. I was up most of the night fighting this problem. I chatted with Intel and never could figure it out. This board is new out of the box. I am using Corsair 1.5 volt 2- 4 gig boards. In the morning I replaced the memory with a Kingston memory board I had in another computer and the Intel board booted instantly. I put the Corsair in the other computer and now it works also.

      I have read about this problem several times in this community. It is nothing against Corsair or Intel, they are just not compatible at least in this situation.

      Now I have to wait for a new order of memory.

      I have put several hundred computers together at work and about 9 for myself at home. I am beginning to wonder if it is worth assembling a computer anymore.

      So many problems to face, so much frustration.

        • 1. Re: DP55WG error 21 won't boot

          We have not confirmed any problems with Corsair memory modules. Are you sure they are compatible with your processor?   Intel(R) Core(TM) i5 processors/Intel(R) Core(TM) i7 processors are sensitive in regards to RAM that does not meet their compatibility requirements.  The first generation of Intel(R) Core processors (the ones that work on your motherboard) are limited to 1066/1333Mhz RAM, with a voltage of exactly 1.5V.  Any module that is rated at 1600Mhz+ or 1.6V+ by the manufacturer, might not work correctly on the motherboard, even if you manually configure it to approved specifications.


          Also, We always recommend sticking to the tested system memory list we provide for each motherboard. You can find the Intel® Desktop Board DP55WG compatibility list here:


          • 2. Re: DP55WG error 21 won't boot

            The Kingston memory board I put in the DP55WG that made it work had identical specs to the Corsair memory that I took out.

            1.5 volts, 1600 (PC3 12800). The only difference was that the Corsair was two 4 gig boards and the Kingston was one 2 gig board. I had already tried switching the Corsair boards and then using them one at a time.

            So the only difference that allowed the DP55WG to work was the brand of memory, not the specifications. I have since sent for two more Kingston boards. I will see how that goes.

            I am using an Intel Core i5-760 2.8Ghz 8mb  LGA 1156 95w Quad Core BX8060515760 processor. It maybe that the problem is processor related, but it still seems like memory brand is the only variable.

            The computer I put the two Corsair memory boards in and they worked, is an AMD machine.


            It's almost as if they try to make building a computer from parts as difficult as possible. The board shows certain specs on memory, but then you have to be careful because the specs for the processor may be different. The motherboard clearly spells out the requierments, but the processor does not.

            Do the manufacturers have something going to push everyone in their direction?

            Even lots of research still produces unacceptable results.

            • 3. Re: DP55WG error 21 won't boot

              I apologize for the inconvenience you've had with this. As you can see on the motherboard specifications, DDR3-1600Mhz RAM is also not supported:



              This speed of memory may work, but we provide no guarantee that it will, and you will be stressing the components, since you are running them outside of the recommended specifications. Please bear in mind that the warranty may be voided.

              • 4. Re: DP55WG error 21 won't boot

                My main problem was the speed. It has to be 1333 or less, but the computer information online and the manual states that 1600 may be used. Kingston memory is far superior to other brands. I spoke with a local computer repair man who has been working on computers his whole life and he said he only uses Kingston and he eliminates any memory problems that he once had. In particular he said Intel motherboards are very particular and

                Kingston works best in them. I now have 12 gigs of Kingston 1333 memory in my new DP55WG and it runs great.


                The difficult part is finding this information the hard way. I spent $200+ on memory boards that should have cost $80. I have since sent most of them back for a refund, but what a headache! The joys of computer building.....

                • 5. Re: DP55WG error 21 won't boot

                  I apologize for all the inconvenience you had with this system, but I am glad you were able to solve the problem that you were having.

                  If you still have the links where you found DDR3-1600Mhz as supported, please provide them to me so that we can correct it.

                  • 6. Re: DP55WG error 21 won't boot

                    PDF document: 1.1 Overview, 1.1.1 Feature summary, Feature 1./ Memory:




                    I am used to relying on company documentation for specs I need. I know it is not always correct, but it should be most of the time.

                    • 7. Re: DP55WG error 21 won't boot

                      Allow me to clarify this confusion, chrislind2.


                      The Intel® Desktop Board DP55WG (by that I mean the motherboard and the RAM slots on the motherboard), supports 1066, 1333 and 1600Mhz.  On previous motherboard generations, the Memory Controller used to be located on the motherboard itself, it was referred to as the MCH or Nortbridge.


                      This Memory Controller was moved to the processor on newer motherboard generations. This provides much better communication and performance between the processor and the RAM. Due to this change, the processor must be taken into account when determining system memory compatibility.


                      Intel(R) Core i7/i5/i3 processors on the 1156 socket currently only support up to 1333Mhz RAM. The additional support for 1600Mhz on the motherboard was added to support newer processor features. The memory may also be overclocked to 1600Mhz, but this is considered an out-of-spec configuration, otherwise known as overclocking; which is not supported by us technically.  In other words, the motherboard may work at 1600Mhz with a 1333Mhz processor, but we do not confirm that it will, as it is outside specifications.


                      For further product compatibility reference, please check the processor specifications as well as the motherboard requirements, to ensure the memory you purchase is fully compatible.