I have a Gigabyte GA-P55A-UD4 motherboard with an Intel Core i7-860 CPU and 4GB DDR3 1600Mhz RAM. I'm currently running the memory at SPD default 1333Mhz, 1.5v and CL9 timings.
Wikipedia and certain other sources seems to indicate that my CPU should run with 1333Mhz memory, but we're past the FSB days here... and I'm not quite sure how to tell how high Mhz memory I can actually use (without overclocking).
I can enable XMS "Profile 1" in the BIOS and then the memory sets itself to 1600Mhz, 1.65v and CL9 timings. That's the proper settings for my memory chips. But, is this overclocking? I don't want to void my warranty and fry my computer.
I know the performance in most situations isn't affected much by the difference between 1333mhz and 1600mhz, but I want optimal settings regardless. Ya know?
ASUS seem to indicate that I could run up to 1600Mhz memory on their ASUS P7P55D-E Pro motherboard. Gigabyte, on the other hand, doesn't seem to offer any such information what so ever for their motherboards. But, it's the memory controller in the CPU that decides this, isn't it?
I don't even know if I'm confused here. That's how confused I think maybe I am.
Technically moving up to 1600 MHz is consider overclocking. 1333 MHz is the highest frequency supported by Intel. Yet the motherboard manufacturers allow you to move easily up to 1600 MHz if you have an i7 860 or i7 870. You don't have to use XMP either. You can manually set the appropriate values. With the i7 860 changing your memory multiplier (SPD) to x12 will cause it to run at 1600 MHz. Then you'll want to set the voltages and timings by hand as well. Give me a link to your RAM and I can help you with those settings if you like.
Another alternative is to keep your frequency at 1333 MHz and see if you can run tighter timings. Lowered timings would tend to give you more benefit, but either way is relatively small (unless you can squeeze alot out of your sticks) so its up to you.
Finally, last option is to keep it as is. Be content with the default specs and the lower voltage that the sticks run at (and lower temps as a result).
Your very first sentance confirms my suspicions. I don't wanna overclock my brand new baby quite yet, so I'll keep my 1333Mhz speed. But as you say, the timings could possibly be tweaked... to maybe CL7?
My chips specs.
Corsair XMS3 DDR3 1600MHz 4GB CL9Kit w/2x 2GB XMS3 modules, CL9-9-9-24, for Core i5 and i7, 1.65V, Intel XMP
Just to make sure I was clear - with your i7 860, the CPU will not be OCed to get your RAM to 1600 MHz. It's just the RAM that will be OCed. And its rated by Corsair to run at 1600, although using the max voltage Intel allows.
Hitting CL7 might be wishful thinking, but I don't know what you'll be able to hit. If you do try to tighten them, take it one step at a time. And you'll more than likely need more V. Bump it up, then if it's stable you can try to bring it down a little. Just don't set it the DIMM V higher than 1.64 V.
I gotta say that's messing with a head a little bit. Nice to know that the CPU doesn't get OC'ed as well though. But then again, if the memory should fry, chances are that other parts will take damage as well. As far as I know.
The memory chips can be run at 1600mhz and 1.65v @ CL9, but that's apparently overclocking by default? Are these 1600Mhz chips really just 1333Mhz chips overclocked by factory default?
They're 1333 memory chips that Corsair has certified as being capable of running at 1600 MHz. They shouldn't fry on you.
I hadn't done a lot of tweaking of my RAM for a while so i went in and resest mine. They're also 2x2GB 1600 CAS9's (9-9-9-24) but from G.Skill. I dropped the frequency to 1333 and tightened the timings to 8-8-8-24 1T and ran it through 5 passes of Intel Burn Test without issue (and a whole 8 seconds faster than before). Not necessarily an extensive but a good quick first check.