Question Ram speed Inconsistant

[Skudd]

Hi there, Just put in two new 8gb ram sticks with an old ram stick. The two new sticks are 2666mhz and the old one is 2133mhz. Looking on cpu z and the clock speed is all over the place. Jumping from 800mhz to 1300mhz and to 3400mhz. Does anyone have an answer for this? Thanks

 

[Darkbreeze]

That's one of the problems with mixed memory, however there are some things you can try.

What are your full hardware specifications including CPU, motherboard, memory kit part numbers and BIOS version for your motherboard?

 

[Skudd]

Motherboard is a Z170-HD3-CF. Cpu intel 6700. Bios version F6. How do you check memory
kit part numbers?

 

[Darkbreeze]

Download CPU-Z, install it, run it, click on the SPD tab and then select a DIMM slot from the drop down menu at the top left. Each DIMM slot will give you different information in the specification fields for that slot. Two of them SHOULD be the same, for the pair, and then one should be different for the oddball.

Obviously, it is up to you if you wish to update the BIOS, but I would recommend that you update to the latest version, F22f. Keep in mind that if you do so you cannot downgrade backwards beyond version F20 and overclocking seemed to work better on F6 but since you have a locked CPU anyhow, that probably isn't even a consideration.

 

[Skudd]

okay, sweet so ill update my bios because I havnt even overclocked my ram so that shouldn't matter. Part numbers for the new ones are KHX2666C16/8g and the old one is KHX2133C14D4/8G

 

[Darkbreeze]

Not the RAM. I was referring to overclocking the CPU. For the memory, I would REALLY recommend that you are probably MUCH better off if you ditch the oddball 4GB memory module and just use the matched set of DIMMs, and then ENABLE the XMP profile for that memory kit in the BIOS. That will not be affected by updating and in fact, memory compatibility will probably be improved. You are much better off that way because you will have 4GB more memory than you currently have, plus you'll have memory that is running in dual channel AND it will be running at 2666mhz.

If you use that oddball memory module you MIGHT lose the dual channel operation, and you CERTAINLY will be running ALL of your memory at only 2133mhz.

IF that oddball stick was also 2666mhz then it would be worth trying to see if your board supports FLEX mode, so that you could run the two sticks in dual channel while that stick runs in single channel, because dual channel doubles the memory bandwidth and offer a nice bump in performance, but since your old stick is considerably slower it is not worth the attempt because it will negate any dual channel benefits by dropping the clock speed across the board.

You can try to add another set of sticks later if you find you need more than 8GB, OR, better would be to simply get a 2 x8GB kit later if you find this is not enough memory.

 

[Skudd]

Thank you. The old stick is an 8gb and my two new ones are 16gb all up (8gb each) so ill still have 16gb without the old one anyway. But I still got the message don't use the old one as it's not really worth it. It seems weird because when I have all three in, CPU-Z still thinks im running in dual channel. I guess it must have FLEX mode?

 

[Skudd]

So if I used the two new sticks and enable XMP Profile should I still update my bios?

 

[Darkbreeze]

That's up to you. If you use only the new sticks, and they are showing up at the correct speed when you enable XMP in both the BIOS and in windows, and there are no obvious problems, then it's not really necessary except that the newer BIOSes do have patches to ward against the Spectre and Meltdown vulnerabilities, but after your current BIOS version, any of those newer ones that are patched will also have some minimal loss of performance attached to them as well because they affect hyperthreading performance. I'd probably just stick to the current BIOS version unless there is a need to update. But either way is fine. Mine is updated and any system I work on gets updated just so I have no liability for them not being updated if I built the system.