Matching dual channel kits?

[Guest]

Hello,
I recently bought a 2 x 1Gb 1600MHz CL9 1.80V Corsair Dominator kit, and I'm looking for another 2 x 2Gb 1600 MHz Corsair or Mushkin kit. Should I buy a matching 1600 Mhz CL9 2 x 2Gb Corsair? It will work with the first one even if it's another manufacturer or latency, i was thinking CL8, it will be slowed down by the CL9 kit? What if it will be one with 1333 or 1800 frequency?
It will have to work with my Phenom II X3 720 and Asus M4A79XTD EVO.
One last question: if in my mobos specs says 4x Dual Channel DDR3 (1800 O.C./1600/1333/1066 MHz) that means it will not work with 1800Mhz RAM just with 1600Mhz oveclocked to 1800?
Thank you!

 

[jsc]

Always try to exactly match new memory to old. If different manufacturer or latency, it may or may not work. If it does work, it may or may not work as well.

 

[Mongox]

And if you bought 1800 RAM, it would default to 1600 anyway because of the presence of the older 1600.

Although it's possible, I think, to OC 1600 RAM to 1800, the "1800 OC" normally refers to having to make OverClocking settings in the BIOS to make 1800 RAM run in the system at 1800. Meaning there's not a "1800" speed setting in the BIOS but you can achieve the speed by manipulating other settings. I believe that's correct but haven't experienced it myself.

 

[Guest]

OK, thanks! So it's better to match them both kits. So my Asus doesn't support RAM that's already at 1800 Mhz.
For the sake of our discussion, has anyone tried different manufacturers DDR3 kits, same speeds (do they have to be same voltages?)? Any examples of both succesfull and unsuccesfull marriages?

 

[Mongox]

There may be motherboards that will supply different voltage to different DRAM slots, but I'm not aware of them. So that's something that I'd make sure is the same. The same is true for the timing - most boards time all the RAM the same. And they all set the speed of the RAM according to the lowest speed present.

I don't use DDR3 myself, so wouldn't have any experience. I just got in some new DDR2 1066 to replace some slower timing modules. For a lark (since I have Win XP and can't use 8GBs anyway) I tried adding the slower modules as the 3rd and 4th sticks. They'll run, but not as 1066 - that hangs up the boot terminally. If I preset the speed to 800, they'll boot but that's all I know. The computer did fail to POST twice and took a long time the other times. I can't test them together except in DOS/memtest86 (since Windows isn't going to show me but the usual 3.25GBs) and don't feel it's a good way to spend the hours! The old ones are going into the mail in 30 mins to make sure my RMA doesn't run out.

Let's say you have a twin-engine plane. The design specs call for a matched pair of either Pratt and Whitney or Rolls-Royce engines. Each has its advantages. Is it possible to put a PnW on one wing and a R-R on the other? Maybe, but you'd have to adjust the trim manually, change the airfoil perhaps, etc... Would you want to ride on this plane?

If you can get matched RAM, I'd recommend it.
If you cannot, then find the best match you can. Make sure the new RAM will run at the other RAM's voltage - or vice versa, chk the old RAM by itself at the new RAMs voltage. Get close timings since you're gonna have to choose one or the other or some point in-between.