Optiplex 780 & 8GB DDR2 800MHz?

Hi navaro's, Having looked at your manual HERE, it says you can only use the DDR3 1067MHz.

Thanks for the replies.

The fact is this, I can get 1066 and 1600 MHz DDR3 memory from the same brand, model and specifications at the same price. My question is: Can I use 1600 MHz memory working @ 1066 MHz in this computer? I think could be more useful the 1600 MHz memory to reuse it in the future.

Thanks.

No, you are correct. You will need 8GB (4 sticks of 2GB) of 1066MHz.

So, if I want 8GB I must get 1066 MHz memory because 4 dimms 1600 MHz won't work, Am I wrong?

You can only if you leave at least one of the 1066MHz chips in. If you use all 1600MHz then they won't down-clock to the 1066MHz speed otherwise.

OK, thank you very much.

You can use 4GB sticks in  a 780 but you need to update BIOS to A05, and 1333 and 1600 both clock down to 1066... its a MB/Chipset limitation

A bit of clarification: He said it will down-clock IF you leave 1066 chips in, so it would seem you could do 2x1600 + 2x1066 and you would be fine. From my experience, you don't have to match all 4 of the memory sticks - just match "each pair." 2 black slots = 1 speed, and then 2 white slots = the other speed.

And, as far as putting ALL 1600 memory in, his answer is "just a [guess]," since he hasn't tried it. Some system in the past would allow ALL sticks to be 'faster memory,' but would not go any faster than their spec - i.e. 1066 in this case.

Regarding these newer - 780, 790, 960 systems, I don't know how that would work - or IF it would work; but, from my own experience (in the past, not with 1066/1600 [I have 1066 in my 780),  mixing slower + faster was okay, as long as you matched each pair (2x1600 & 2x1066, for example).

Okay, now I'm TRULY confused - you said he can use 1600 *IF* he leaves in some of the 1066 sticks, so your own answer is wrong - you said, "No, you are correct. You will need 8GB (4 sticks of 2GB) of 1066MHz."

But, from  your earlier answer, it seems that he could have 2 x 1066 2GB sticks; and 2 x 1600 2GB sticks, for a total of 8GB, and it would down-clock to the lower memory speed - right?

If so, then NO, he does not have to get 4 x 8GB 1066; he can get 2x1066 and 2x1600.

I'm with him - I am seeing some REAL deals on the 1600 memory, and I could care less if it down-clocks, I just need the extra memory - plus, he make an excellent point about using it in future upgrades - great way of thinking ahead!

Try your sticks one at a time.  Might have one DO out of the box. 

DOA not DO