Matching RAM to M/B

[jacques_za]

Hi Guys,

Getting a new PC soon, and it seems I've lost track on how complicated buying memory has become!

I'm looking to buy memory for my Asus P8Z68 Deluxe Gen3 Intel Z68 motherboard, but we don't have the entire G.Skill memory range available in my country.

The board supports a maximum of DDR3-2200 memory, but I can only buy either

G.Skill F3-2133C9Q-16GAB 16GB (4x4GB) DDR3-2133MHz 1.5V CL9 Quad Channel Ares Desktop Memory
G.Skill F3-19200CL9Q-16GBZMD RipJawsZ 4x4GB DDR3 2400Mhz 1.65V XMP X79 Ready Desktop Memory

Which would produce better results?

Can I buy a faster memory set and just run it slower, or should I buy something that is officially supported?

Regards.
J

[Tradesman]

Either will work, make sure you have the latest BIOS, with the Ares you'll install, enable XMP and select profile 1, with the RJ Z you'll install, enable XMP and try profile 2 which may work. If it doesn't work, disable XMP, set them to 2133 and try 8-10-10-30 or 9-10-10-30 with CR at 2T and DRAM voltage at 1.65 (may be able to drop to 1.6, VCCIO or CPU VTT (not positive what the MC (memory controller) voltage is called on this ASUS mobo) about 1.22

[jacques_za]

Thanks!

I'm actually trying to hit 2200, which seems to be the highest that the motherboard supports. So I'm thinking that the DDR3-2400 should be able to run at 2200?

What are the chances that I can run beyond the motherboard spec? I assume that if you can clock the CPU past the factory clock, then surely you can do the same with the memory?

What memory would be the *best* for that motherboard (not just from the two I'm listing). I'm trying to understand how to pick ram. I've always assumed that the clock speed was the thing to look for, but now it seems the CL timing is also important, but I don't know how to factor it into the decision.

[Tradesman]

Generally I look for the fastest freq at the lowest CL (CAS Latency) - roughly as freq speed goes so does CL, so if you chose say 1866 at CL9, then dropping to 1600 @ CL8 is very close as is 2133 @ CL10 - with the higher freq it will have a little better bandwidth. So, if you pick up 2133 at CL9 it's better than getting 2133 @ CL10 or getting 1866 @ CL9 and OCing it to 2133/CL10. The reverse is true also, if you go 2400 at CL10 then you can fairly easily downclock to 2133/9, 1866/8, 1600/7 - a lot depends on budget, what the mobo will support and if you plan to upgrade in the future as to mobo and/or CPU, i.e. a smokin' deal today on 2400 might be the ticket, even if your mobo can only run 1866/2133 but if you are looking to a new mobo and/or in the near future