9 Replies Latest reply on Jun 21, 2011 2:14 PM by ibrahimzz

    need help choosing right cpu/ram configuration


      hi all


      i have been looking at a wide range of cpu's and i am having a problem with choosing the right ram

      most of the cpu's that i seen say on their memory specification

      Memory Types

      DDR3-1066/1333     i5-680

      does that mean i can only insert ram that is the same as the above

      i wanted corsair's dual channel kit 2x4gb 1600mhz would this work on this cpu

        • 1. Re: need help choosing right cpu/ram configuration

          That processor will only support 1066 / 1333, that means that if you install RAM running at 1600, if it works it will be running at 1333, but we cannot guarantee that it will work, so we recommend buying RAM running at 1066 or 1333.

          • 2. Re: need help choosing right cpu/ram configuration

            so if i install a ram thats at 1600mhz the cpu limits it to 1333.

            i know this because i have seen people use 1600 on cpu's that support only 1066/1333 it just basically limits the ram from its full potential.


            it's quite a shame to see all 1156 cpu's support only 1066/1333 unless their is one out here.


            thanks for the reply

            • 3. Re: need help choosing right cpu/ram configuration

              I agree with Adolfo w/ the Ram Issue; But what seems Like a right answer for Custom Build's Isn't always the case. Being a Custom build "Myself", I some what know what timing Issue's curtail. Here's my custom Scenario & what I did. First in picking parts from vendors I figured an I 5 core 670/1156 socket & a DP55WG series Media Board 8GB. DDR3 would be thye most universal of Intel Boards too work with. I specificaly ordered that Series Board for Dual PCI-Bus Express Graffics; In which I run Dual 1024mb GDDR3 9600 GT's.on 270.66 Driver's. Some people may say those Graffics Card's are Junk; But I'll prove them wrong. I'm using both Raid w/ Rapid Storage.I'm running an Audigy 4 Soundblaster w/ Latest High Definition Audio Device Driver's w/ Custom Preset's. The Ram Spec's I Chose to use couldn't have been better! I give a thumbs up too Patriot Memory. I chose PC3-12800/1600Mhz w/ Enhanced Latency. The Timeing was the reason why....I chose a  Seagate Barracuda Sata/1TB/TO 7200 RPM 32 MB Cache. Like Adolfo Suggested I limited Full performance & Dealt w/ Timing Issue's by simply Adjusting the jumper and limiting my hard drive speed so clocked properly w/ the Processor/Ram/Dual Pci Bus Express & NTFS Format. But you have too keep in mind XP Pro is a great OS; And didn't have a ton of money too Invest in Hardware & Software like some people do. Sure I knew that running XP Pro wouldn't allow my Duel Graffic's SLI Phys-EX Build too run Direct X 11; But that's simply because at the time I couldn't afford the Extra $300.00 for Windows 7, When all was said & done. When & If I do; They Will support  Direct x 11. By the way; Monitor's1080 DP Full HD Visio/My Drive's CD-R/DVD/RW Blue Ray Digital Sata/Serial-ATA. I couldn't have built a more stable,Gaming/Media Machine. I hope my approach help's solve someone's Problems....Thumbs up Intell!.......Sincerly,....Shard.....

              • 4. Re: need help choosing right cpu/ram configuration

                If you were to check the memory specified for the Intel i7-990X Extreme series processor, for $1000, it is 1066.  The memory specified for the latest Xeon server processor, the E7-8870 with 10 cores, plus hyper-threading, uses four channels of memory, and costs $4600, is 1333 memory.


                Those specifications are the memory speeds which the CPU is guaranteed to work at, and are conservative.  The speeds of 1066 or 1333 are standard or default speeds for DDR3 memory.  DDR2 and DDR3 memory contains a separate data chip that contains information about the memory, such as it's speed and the correct timings to be used with it,  That is called the SPD data, and the specifications for that were created by an organization called JEDEC.  The SPD data usually contains several sets of data, for different speeds the memory is able to run at.  For example, memory that is able to run at 1600 will be able to run at 1333 or 1066, so there usually is SPD data for the lower speeds.


                Memory manufactures have an issue when they sell memory that can be used at speeds beyond 1066 or 1333, for example 1600.  They have no idea what kind of PC the customer will be using with the memory, or how much that person knows about PCs.  All PCs cannot use memory that runs at 1600 or beyond, they will not boot or will BSOD, which is usually a limitation of the mother board, not the CPU.  So, the memory manufactures set the speed settings of the default SPD data to 1066 or 1333 to ensure they will work in all PCs.  The PC's BIOS at default settings reads the default SPD data and uses that speed.


                But that 1600 memory also has an SPD data set for running at 1600.  For it to be used, the user must change one or more BIOS settings, and the memory will run at 1600, assuming the PC can do that, and most better PCs can.  That data set or profile is called the XMP data, which was designed by Intel.  Any good mother board's BIOS has an XMP memory setting in it, just change it from Auto or Default to XMP, and all the correct settings for running at 1600 will be loaded and used.  For DDR2 memory, the "performance" memory profile is called EPP.  You can also set these timings manually in the BIOS.


                I use 1600 memory in two of my PCs, using the XMP profile with Intel CPUs, and they work just fine.  If you have a good mother board, you can run your memory at 1600 with an 1156 CPU, as long as the memory is capable of that speed.  There is DDR3 memory capable of speeds of 2000 and beyond available now, and is used by enthusiasts with Intel CPUs rated at 1066 or 1333.


                A reality of memory is at speeds beyond 1600, there is little or no gain in performance shown by various testing methods.  Actually, the best overall speeds to use are 1333 and 1600.  As long as your mother board's BIOS allows you to use the XMP profile in the SPD data, or allows you to set the speed manually, the CPU itself will not automatically limit the speed of memory you use.

                1 of 1 people found this helpful
                • 5. Re: need help choosing right cpu/ram configuration

                  thanks for the reply


                  i was thinking of getting 1333mhz ddr3 ram and over clocking it so it will be compatible with the cpu because the original speed is  1333 and making it higher wont be a problem with the cpu.


                  and one more thing if most cpus out ther only support 1066 and 1333 why make 1600 and 2000, 2133 this stuff is confusing me realy badly why waste the money for the extra mhz when you gona be limited


                  the motherboard that i got is msi big bang trinergy it supports up to 16gb of ddr3 ram and 2000mhz+ that motherboard was quite exspensive and i am sure it will let me take 1333 memeroy and kick it up a notch

                  • 6. Re: need help choosing right cpu/ram configuration

                    My point is you are not limited by the memory specification of the CPU, the limiting factor, if any, will be your mother board and the options in it's BIOS.  You also seem to be thinking in terms of socket 775 CPU architecture, when you mention over clocking, which sounds like FSB speed changes.  The i5-680 CPU does not use the FSB architecture, it has an Integrated Memory Controller (IMC), and the link between CPU and the PCH, or very generically speaking, the northbridge, is with a DMI link.  The picture below is from the i5-680 specification page:




                    The speed of the memory "bus" is not dependent on any clock or bus frequency that is shared by other components in the CPU/supporting components system, it is independent.


                    Given your mother board, you'll be fine with your memory.  DDR3 memory tends to be not very over-clockable in my experience, meaning above the stated specs, so if it doesn't go much above it's advertised speed, it won't be the CPUs fault.  The memory manufactures have the memory chips "binned" to the point that we are forced to buy the faster spec'd memory if we want that speed, they aren't giving away faster memory at lower prices anymore.  Check the forums on MSI's web site, or your memory manufactures web site to see what users are able to achieve.


                    They wouldn't sell 2000 memory if the CPU limited it to 1333, so it does work.  Don't forget the market for that type of product is very small compared to what is used in 99% of PCs.  You should not worry about that memory spec for your CPU, check those forums and see for yourself.

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                    • 7. Re: need help choosing right cpu/ram configuration

                      ok thanks for all the info helped alot and learned alot 1333 is more than enough for me.

                      i have chosen my cpu i7 875k

                      • 8. Re: need help choosing right cpu/ram configuration

                        Hello , What  is the best Memory for MB:DP45SG ?  Can i use Geil 2GB x 2 DC Kit 1600MHZ?  Memory Model is GVP34GB1600C9DC

                        Thanks a lot