1866 Ripjaw Z on my Sabertooth x79

[prkaye]

I just set up a new system based on a Sabertooth X79 MB. I bought a 32GB kit (4x8) of GSkills Ripjaw Z, 1866MHz.
My bios sees the RAM, but with clocking set to Auto it only runs it at 1333MHz. When I set it to manual - 1866, the system becomes totally unstable (no video and machine continually rebooting itself). I cleared the CMOS (the little jumper) and then reset the RAM clocking to 1600MHz and the machine seems stable now (at least in the bios, i don't have an OS installed yet.
The ASUS guy tried to tell me that because my specific RAM kit isn't on the QVL, they can't guarantee it will run at the rated speed. But there are hardly any 32GB kits listed on the QVL!
Questions
1) should I be surprised that my RAM is not running at the speed it's rated for? Does this suggest something is defective?
2) would I be better to exchange this RAM for actual 1600GHz RAM, or is underclocking the 1866MHz RAM just as good? (keeping the faster RAM and underclocking it saves me a restocking fee).

 

[alexoiu]

Have you tried setting the XMP in BIOS?
Running the RAMs at 1600 is just as good. If you install the CPU-Z you'll be able to see the RAMs profiles (JEDEC and XMP).

 

[prkaye]

Have you tried setting the XMP in BIOS?

No, I wasn't even aware of that. Is it as simple as going into the BIOS and setting "AI Overclock Tuner" to "X.M.P"? If I do this, do I need to change my RAM clock speed back to Auto? Apologies - I'm very new to this stuff.

 

[alexoiu]

You can set it back to Auto, then the Ai to XMP. It will automatcally adjust the necessary settings accordingly.

 

[prkaye]

THANKS!!! This seems to have worked (setting it to XMP). Now I get into the bios and the RAM shows as running at 1866. If it remains stable like this when I get my OS installed I'll be one happy camper!
I can't believe a half-hour on the phone with the ASUS tech and he never mentioned this. He basically said "sorry, you're going to have to run it at 1333 since that exact RAM is not on the QVL. Where do they find these guys??

 

[prkaye]

One more question - is there any risk of damaging the memory controller on my i7-3820 buy using XMP to clock my RAM up to 1866MHz? Could I fry the memory controller on the CPU?

 

[alexoiu]

The temperature will raise a little bit, but you can run a monitoring program (try HWMonitor) and check the temps while idle and under load. Actually you can test with XMP disabled and then enabled and see the differences.

 

[Guest]

One more question - is there any risk of damaging the memory controller on my i7-3820 buy using XMP to clock my RAM up to 1866MHz? Could I fry the memory controller on the CPU?

absolutely not, you're actually better off running XMP.

 

[prkaye]

Well, I ran memtest 86+ today on the RAM clocked to 1866 with XMP. Memtest gave a few errors very quickly (tests 2 and 3). So I went back in and left XMP on but manually changed the ram frequency down to 1600, leaving all other settings the same. I'm an hour into a memtest pass now (44% through the pass) and so far no errors.
I wonder, could this be that my Core i7 3820 memory controller was having trouble keeping up at 1866? The Intel site says that CPU is only officially rated for up to 1600MHz RAM. If it passes the memtest, I can keep it and underclock it to 1600 - just means I overpaid by about 30 bucks for the ram