What is XMP?

[JohnJSal]

Yes, DDR3 motherboards can only default to DDR3-1600 CL11 max, so if you have DDR3-1600 CL9 memory, you still need to enable XMP or manually input timings 9-9-9-24, otherwise the system will operate at standard 11-11-11-30 timing values.

So either way, as long as you have performance memory (better than DDR3-1333 CL9), you should always enable XMP or manually input settings. Doing so will not harm your computer in any way, if you accidentally input the wrong settings, the system will not boot properly and you will just need to try again. It's no big deal.

Thank you
GSKILL TECH

Thank you very much! I'm glad I know these details in advance, so I wouldn't have to wonder what's wrong later. Although I doubt I would have even noticed a speed difference, so it's good to be told these things.

[Tradesman]

Keep us updated on your progress

[fred kres]

It may seem like JohnJSal is asking simplistic questions, but the answers are helping me a lot but not completely. I'm planning my first build and I'm terrified of trying to understand what will happen with different RAMs -- the compatibility issues and the confusing terminology are scary. For an Asus P8Z77-V Pro mobo using a i7-3770k cpu I was thinking of options:
[ RipjawsX] F3-17000CL9Q-16GBXM (4GB x 4) tested speed DDR3-2133 PC3 17000 @1.65v; SPD 1600mhz @1.5v
[ RipjawsX] F3-2133C9D-16GXH (8GB x 2); Tested DDR3-2133 PC3 17000 16GB CL 9-11-11-2N 1.6V;SPD Speed 1333 mhz @1.5v
[ RipjawsZ] F3-12800CL9Q-16GBZL (4Gx4); DDR3-1600 PC3 12800 16GB(4GB x 4) CL 9-9-9-24-2N 1.5V; SPD speed 1600mhz @ 1.5v
Assuming I turn on XMP:
The 1st should give 2133 mhz or is it only 1600mhz; how is the voltage changed and what is it's impact?
The 2nd is the same 2133 mhz but SPD is 1333 mhz. which do i get?
The last bet gives me 1600mhz only.

Incidentally, G.Skill's Ram Configurator presents (for the ASUS P8Z77-v PRO mobo) a compatibility list of 120 Ram selections in random order - there is NO logic to the sequence of items presented. After trying to find all the 16 GB Dimm's and checking individual details in another window, I am exhausted and seriously considering abandoning G.Skill.
Your people must find a way to allow customers presented with this big a selection, to be able to filter the list on size, speed, SPD, etc, and to sort it by several parameters and provide all the info upfront.
Fred

There is no wa

[Tradesman]

The SPD speed you refer to, is nothing more than the basic default boot parameters....Most every mobo out there defaults to either 1333 or 1600 for booting purposes whenever it detects new DRAM has been installed..so it's really not worth worrying about, or give thought to. With your mobo/CPU combo for 2133 2x8GB I like your choice, the Ripjaws X F3-2133C9D-16GXH, if you decide to go 4x4GB 16GB 2133, then I'd suggest the 2133 F3-17000CL9Q-16GBSR Snipers first (a little higher OC headroom), and your choice the Ripjaws X F3-17000CL9Q-16GBXM, as about equal (I've just had better luck w/ the Snipers in OCing, in fact have a set of these running at 2400 w/ a P67/2500K combo. At 1600 basically any of the sets will be fine, and I personally have no real overall pref (except again with the Snipers for Over and Under clocking

[JohnJSal]

Well, the upgrade went great, no problems! However, I noticed this line in the XMP sticky:

"Before enable XMP, please update with latest version of Motherboard BIOS and clear the CMOS."

Is this necessary? I'd rather not mess with upgrading the BIOS or getting back into my case anymore, just to do this.

Thanks.

Edit: My board is a Gigabte GA-Z77X-UD5H

[Tradesman]

If you're good and operating OK no problem,,,big thing w/ BIOS these days is ongoing DRAM updates to get things right particularly with 8GB sticks and amounts from 16-64GB

[JohnJSal]

If you're good and operating OK no problem,,,big thing w/ BIOS these days is ongoing DRAM updates to get things right particularly with 8GB sticks and amounts from 16-64GB

So far so good. It's been two days. Also, my memory is two 4GB sticks.

[Tradesman]

I'd prob let it go....if any problems crop up give us a shout...

[JohnJSal]

I'd prob let it go....if any problems crop up give us a shout...

Thanks much!

[Tradesman]

No problem, keep us updated