When I use CPU-Z it lists the DRAM frequency much lower then it is supposed to be, and says "channel # single" does this mean it's running in single-channel mode instead of dual?

Also in memtest while it doesn't list any errors it sees the RAM as an even lower speed, and as DDR2 instead of 3. are these programs misdetecting the hardware or is there a serious problem with the RAM modules?

  • How low does CPU-Z list the RAM frequency? Like, half of the actual frequency? Are you saying that memtest says DDR2 and CPU-Z says its DDR3 ? – Varaquilex Dec 26 '13 at 1:04
  • unless I'm reading it wrong it says 877Mhz. there's a different value that says "nb frequency" that's at 1449.7Mhz, but I don't know what NB means. – ZCoder Dec 26 '13 at 1:07
  • Is it on Memory tab or SPD tab? What does it say on SPD tab? – Varaquilex Dec 26 '13 at 1:09
  • that's the memory tab. in the SPD tab for both modules anything referring to speed is in the 800-900 MHZ range. – ZCoder Dec 26 '13 at 1:11
  • 2
    With all DDR RAM, the effective transfer rate is twice the frequency. If it's, say, DDR3-1600 RAM, the frequency should be 800MHz. – David Schwartz Dec 26 '13 at 1:28

When you buy a RAM module (say DDR3-1600 MHz), you buy a memory module that has a theoretical speed of 800 MHz. That's the way it is, when you are buying, the naming has the value which is double the actual operating frequency. The reason behind this is the RAM being DDR: Double Data Rate. They transfer two chunks of data in one clock cycle.

Now knowing that you have a theoretical speed of 800 MHz, you should also keep in mind that it is theoretical, not practical.

enter image description here

Take my DDR3-1600 MHz RAM for example, it has a 800 MHz theoretical frequency (which you can see on SPD tab) and it actually operates on 532.1 MHz.

There is also another issue about RAMs when the modules installed on your system are not operating at the same frequency. The RAM operating on lowest frequency determines the bus speed for CPU-RAM communication. So if you install a, say DDR3-1033 MHz RAM beside your DDR3-1600 MHz RAM, the bus will adjust to the 1033 MHz one. Thus, it will not be optimal for the DDR3-1600 MHz RAM. In addition, the system won't be able to use Dual-Channel architecture and your CPU-Z program will display Channel # as Single, not Dual. This is the reason you should choose identical RAMs for your system.


I have looked up your motherboard's manual.

enter image description here

It states that you should first populate the black-color-coded slots first. So installing the modules on DIMM1 and DIMM3 (blue slots) may have caused your problems.

enter image description here

| improve this answer | |
  • that's odd, as the readings for both RAM modules are the same. they came from a 4GB "kit" that consisted of 2 2GB DDR3 modules. if they weren't identical, the definitely should have been – ZCoder Dec 26 '13 at 1:25
  • Did you install them on laptop or desktop? If it's the desktop case, you should see this answer, you may have an answer there if it's the case that you are installing your RAMs on different channels. – Varaquilex Dec 26 '13 at 1:27
  • both modules are seated in Blue sockets- should I try moving them to black ones instead? (sockets from left to right: Blue,Black,Blue,Black) – ZCoder Dec 26 '13 at 1:29
  • You may try that and see how it goes. What's your motherboard? – Varaquilex Dec 26 '13 at 1:30
  • FM2-A85XA-G43 (AMD A8-6600K) – ZCoder Dec 26 '13 at 1:37

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.