18 Replies Latest reply on Nov 20, 2012 12:34 PM by 0to60tv

    What memory to get for my system?

    Harm Millaard Level 7

      This is a common question when people are building a new system and the uncertainties about compatibility with certain CPU's are numerous. In order to address this issue, let me give you a number of steps you can take to make sure you buy the memory that will in all likelihood do exactly what it is supposed to do.


      1. Make up your mind about the number of memory sticks you want to install. On the X79 platform, do you want to use 4 slots, or do you want to fully populate all 8 slots? This is very important especially with i7-3930K CPU's, which have a rather finicky memory controller.
      2. Make a shortlist of quad or octo packs of memory sticks in the size you want, limiting yourself to ONLY sticks using 1.5V or less.
      3. Check the motherboard manufacturer's site QVL list to see which of the sticks on your shortlist are approved. Pay attention to the number of slots for which they are approved. Some modules are approved for 4 slots only, others for fully populated use.
      4. Check the memory manufacturer's site QVL list to see which motherboards are approved.
      5. Try to establish if there are users that have been successful in using the sticks on your shortlist and delete any that were giving trouble to others. NewEgg can be a good source for that.
      6. Now that you have a very short shortlist, contact the Technical Support departments of both the motherboard manufacturer and the memory manufacturer and ask them to confirm or deny the compatibility of the memory modules in the quantity you need.
      7. If both confirm compatibility, check the physical height of the modules including heatsink in relation to the intended CPU cooler. Do they fit without modding?


      In general, only buy matched sets of memory sticks. There are too many different sticks with the same type number, that will cause grief when bought as four single sticks, but you limit the risk by only buying quad sets or octo sets for fully populated X79 platforms.


      CAS latency is no longer important, in fact, with the finicky nature of the memory controller of the Sandy Bridge-E, it can be advantageous to choose a higher CAS latency for improved compatibility. What can be important - relatively speaking, only in single digit % performance differences - is the rated speed of the memory, 1333 or 1600 or 2133 or even 2400.


      Even though the X79 platform only supports - at least officially - up to DDR3-1600, one can use XMP profiles in the BIOS to have the memory run at its rated speed of say 2133.


      For my new 'Monster' I followed these steps and ended up with a fully populated 8 x 8GB octo set of G.Skill RipjawsZ F3 DDR3-2133 sticks that are running without any problems at 2190 MHz.


      Hope this helps others to make the right choice of memory modules and I would request readers to submit data on their memory modules on fully populated X79 platforms to share with the community. Brand, model, size, speed and the effective running speed. Also please share your experiences in setting up the memory in your system. I for one had difficulty in setting it up correctly as documented here: Final Results

        • 1. Re: What memory to get for my system?
          Alan Craven Level 4

          I run 32GB (2 sets of 4x4GB) of Corsair XMS3 PC3-1600 on a Gigabyte  GA-X79-UD5 motherboard - fully populated.  This is run at its rated speed, for which XMS has to be enabled and is at Profile 1 with Turbo enabled.


          My processor is  a Core i7 3930K and runs at 4 GHz.


          The only problems that I encountered were in the early days before Gigabyte released a suitable BIOS at the end of March 2012.

          • 2. Re: What memory to get for my system?
            Harm Millaard Level 7

            Thank you Alan, these kind of responses may help other to find the answers to their doubts.

            • 3. Re: What memory to get for my system?
              jamesp2 Level 1

              Since the ADK-recommended Samsung 1.35v SDRAM is apparently only available in sets of 8GB (2x4gb), does any user care to comment on 4 or 8 stick installations?

              • 4. Re: What memory to get for my system?
                0to60tv Level 1

                Thanks for this really helpful guide Harm,


                Looking like the gskill ripjaws, just cant decide whether to go 32gb or 64gb IE is the additional ram worth the risk of instability?


                Also, I understand after effects can and does use as much ram as you can offer it?



                • 5. Re: What memory to get for my system?
                  Kris_24 Level 1

                  Thanks very much for adding this guide Harm! Hopefully many people come back to report what works, as I think that will give people the most peace of mind about the issues raised with the 2011 socket/X79 platform. There is a ton of conflicting information out there on what works and not (e.g. voltage rates) and it would be great to have a comprehensive list of known compatible RAM.


                  I'll report back with my own results once I get my system together.

                  • 6. Re: What memory to get for my system?
                    0to60tv Level 1

                    Im so confused!?


                    I thought the P9x79 PRO supported 64gb of Ram...but on the QVL list...it only seems to show up to 16gb??


                    qvl list here...I think




                    I was planning on using









                    Am I right in my assumption that 32gb/64gb "may/will" work, but not officially supported?


                    How much memory can/does ppcs6 actually use...I am under the impression that aecs6 can use 64gb memory...but I use pp a lot more than ae and so would be prepared to trade off some ae performance in exchange for pp stability!


                    your thoughts?

                    • 7. Re: What memory to get for my system?
                      Alan Craven Level 4

                      G.Skill RipjawsZ is designed specifically for the X79 chipset and 2011 processors, so I should think it would be best to use one of those sets.


                      As noted in my earlier post, my Gigabyte X79 motherboard is fully stable with the 8 memory slots fully populated with 32GB of RAM.

                      • 8. Re: What memory to get for my system?
                        El_Plates Level 1

                        The QVA for the P9X79-PRO on the ASUS webite hasn't been updated since last year. That means many RAM kits won't be listed.


                        I called ASUS support; here in Australia, but they can't answer questions about motherboards.

                        They directed me to the International online support pages, but I couldn't find anywhere on the ASUS website where I could ask a question about what RAM kits are currently supported by the P9X79-PRO.


                        The only place to ask them directly (that I could find)

                        is through submitting a Techical inquiry Form.

                        Problem with filling out that form is that it requires a Product S/N.

                        I won't have a Product S/N until After receiving a product; Not before.


                        Today ; after failing to get answers from ASUS, I e-mailed G.SKILL to ask them if they can confirm if their RipjawsZ F3-12800CL10Q2-64GBZL (8Gx8) kit works on a P9X79-PRO / i7-3930k PC.

                        I await their reply.

                        • 9. Re: What memory to get for my system?
                          0to60tv Level 1

                          I'll be installing 32gb of ripjawz (12800, 2 x 4x4gb packs) into that mobo this afternoon if I ever finish with current client! So ill let you know how I get on!

                          • 10. Re: What memory to get for my system?
                            El_Plates Level 1

                            Harm. Here's the information I received from G.SKILL Technical Support, in response to my inquiry.

                            I think you might find it interesting. My question/s asked if they've tested a particular 64GB RAM kit http://www.gskill.com/products.php?index=432 on a P9X79-PRO motherboard with an i7 3930k CPU, and if they can confirm whether that kit works with those components.


                            Here's their reply--


                            Dear Christopher Cox,


                            On our F3-12800CL10Q2-64GBZL webpage (http://www.gskill.com/products.php?index=432), we listed the ASUS P9X79 Pro motherboard as a compatible motherboard. Any motherboard we have listed as compatible has been tested using the i7-3930K CPU. We also put the system through an in-house stress test during production before each of the product is shipped out.


                            So you can be sure that our memory kit will work on your system. We can confirm that  F3-12800CL10Q2-64GBZL is fully compatible on a ASUS P9X79 Pro and i7-3930K system.


                            However, do keep in mind that out of all our 3930K CPUs, there were a few CPUs that had problems supporting full eight modules, regardless of frequency. Strangely enough, they were able to support 2400Mhz at 2 or 4 modules, which is unlikely for Sandy Bridge CPUs. So if you are having trouble with all 8 modules, but not with 4 modules, the CPU might be the cause. A rare occurrence, but would happen with any CPU with integrated memory controllers.


                            In terms of being finicky, the 3930K CPU simply has less tolerance when compared to the 3960X at high frequencies, such as 2400Mhz. At 1600Mhz, there should be no problems.


                            ASUS is not able to list all memory kit models that are compatible because they do not have all of our memory kit models. Therefore, won’t be listed on their QVL list.


                            Please feel free to contact us again if you have any further questions. Thank you for choosing G.Skill.


                            Best Regards


                            Tech Support Team, F.A.E.


                            1. G.SKILL International Enterprise Co., Ltd.
                            • 11. Re: What memory to get for my system?
                              Alan Craven Level 4

                              Very interesting, thank you very much El_Plates.


                              I note that they say that the problems with 3930K and memory are due to varience beteen individual CPUs.  So they must carry out their testing thoroughly,  with more than one CPU of each model.


                              They may just have got themselves a future customer here - I have always used Corsair memory up to now.

                              • 12. Re: What memory to get for my system?
                                Harm Millaard Level 7

                                It would be interesting to know whether the observed tolerances at high speed were improved in the C2 revision and thus reduce high speed problems in the memory controller over earlier steppings.

                                • 13. Re: What memory to get for my system?
                                  El_Plates Level 1

                                  What is that C2 revision you mentioned, Harm? What was it's purpose?


                                  Based on that e-mail from G.SKILL, I'm now more confident in purchasing my build's components, as listed in my inquiry/question I asked them.


                                  I'm still open to the idea of changing my motherboard choice to a P9X79-WS if I can source one at a lower price. Same goes for the CPU. An i7 3960X would be nice, if the price drops (significantly) after Christmas (which is when I plan to purchase all necessary components).


                                  In an earlier discussion I noted one user reporting that his setup is using the above RAM kit with a 3930k and a WS board, and he said that combo is working great.

                                  • 14. Re: What memory to get for my system?
                                    Cocovanna Level 1

                                    Why would you choose a 3960X?

                                    • 15. Re: What memory to get for my system?
                                      Harm Millaard Level 7
                                      What is that C2 revision you mentioned, Harm? What was it's purpose?



                                      Every CPU has some bugs in its design, despite extensive testing. From time to time the most pressing bugs are resolved by making a revision in the design and the C2 revision is the latest model for the i7-3930K, so it should have the most pressing bugs resolved. Somewhat similar to the point releases in CS6.


                                      The new version from CS5.5 to CS6 is somewhat comparable to the Sandy Bridge and Ivy Bridge.

                                      CS6 to CS6.03 is somewhat comparable to the C1 and C2 revisions on CPU's

                                      • 16. Re: What memory to get for my system?
                                        El_Plates Level 1

                                        By the way you described C2, it sounds like a downloadable firmware update, or some kind of data. Is that how consumers get C2? or is it a physical update to the CPU's hardware?

                                        If it's the latter,  then I'd have to guess that newer batches come with C2 installed.

                                        • 17. Re: What memory to get for my system?
                                          Harm Millaard Level 7

                                          It is not downloadable, it is a physical CPU. Of course, you can get a new CPU if your current revision is a C1 revision, but 99.9999999% of the people would consider that crazy. But for new buyers, they can insist on being given the most recent revision, and not an old one from surplus stock.

                                          • 18. Re: What memory to get for my system?
                                            0to60tv Level 1

                                            Just to add to the list of "compatability"


                                            Asus P9x79 Pro

                                            intel core i7 3930k

                                            EVGA GTX 680 Classified 4gb

                                            G-Skill 32gb 8x4gb DDR3 1600Mhz RipjawZ CL9 1.5V


                                            Has been solid as a rock for 12 hours straight editing XDCam ex footage with multiple layers and buckets of effects...