I have several noob questions regarding the "how-to"s of over-clocking and tweaking my system for FSX, but I'll spare you all from most of them as I'm sure you've already discussed them many times. I do however, need a timely answer to a (probably) basic issue before my return-period expires. I'm sure I can track down the remaining info needed (if I can manage to avoid being side-tracked by the wealth of interesting reading here). I'm starting to build a new system but I think I may have bought the wrong memory (still un-opened, from Newegg). It's been several years since I've built a box so I'm a little rusty, especially in regards to memory selection, compatibility and over-clocking, and I was hoping for a quick edification.The memory that I bought is: G.SKILL Ripjaws X Series 16GB (2 x 8GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model F3-10666CL9D-16GBXL.I bought that particular memory because my processor (Intel i7-2600k) indicated that its "Integrated Memory Controller" supported Dual Channel DDR3-1066/1333, leading me to believe that those two speeds were my only choices, even though my motherboard (ASRock Z68 Extreme3 Gen3) supports "DDR3 2133(OC)/1600/1333/1066/800". (On a side note, perhaps you can also explain the meaning of the "(OC)" next to "2133". Does it mean 2133 can only be obtained by, say, over-clocking 1600 to 2133?)My plan is to over-clock my CPU, RAM, and GPU to a reliable maximum while using only air cooling. Can and should I use ram faster than 1333 or would anything faster be wasted by being "bottle-necked" by the CPU's 1066/1333 support?Thank you very much for your assistance.Edit: My bad guys. It never fails; as soon as I posted this, I found the discussion here.

Edited March 27, 201214 yr by HED

Just on the "(OC)" tag, it means that for the RAM to run at 2133MHz you have to overclock. You can buy DDR3 2133 but it will run at a slower speed unless you overclock your CPU.Cheers,Mike

You can buy DDR3 2133 but it will run at a slower speed unless you overclock your CPU.

OC'ing your ram and CPU are two different things. I initially ran my i5 at stock clocks with ram to XMP (1866) without any issues. I also manually set only the ram to 1866 to verify my XMP was reporting right.With that being said, fast ram is just part of the performance equation. You will still need to OC the CPU and GPU to get the most out of the rig. OC's to the CPU can hurt your ram oc (slow ram to stabilize) but the true performance gain in FSX is CPU anyways.To OP, just get good high quality ram that is fast with low timings which fits in your budget. Going from 1600 to 2133 isnt a huge jump in actual performance, but if you can get faster ram do it.

Just on the "(OC)" tag, it means that for the RAM to run at 2133MHz you have to overclock. You can buy DDR3 2133 but it will run at a slower speed unless you overclock your CPU.

Okay, that's the way I was leaning. That being said, it would seem to also hold true not just for the 2133, but also for the 1600 since the SB CPU only supports 1066/1333 (but may not be the case when used with a non-SB CPU/memory controller). I could have sworn that when I was comparing mobo specs that it also included "2000(OC)/1866", but it's possible I'm thinking of another mobo.

Your RAM will run perfectly fine on your mobo, however - I recommend returning it anyway, cuz that RAM is quite slow. Faster RAM will barely make a difference in framerate, but it will make things just a little smoother. And with smoother I mean less microstuttering and hitching. And now probably many people (who didn't test this) will say how wrong I am. Well, I have tested it and got these results. I highly recommend getting 2133 CL9 RAM. Make sure it has low voltage. Corsair RAM kits are known for running stable at low voltages. Intel says that anything above 1.58V might eventually cause harm to the CPU. And with these kit, I have 0.08V to play with to overclock it!

HEDThe main thing to remember about SandyBridge cpu's is that you are ONLY overclocking the CPU multiplier but the the Front Side Bus stays at the same rate so the benefits of faster RAM and overclocking RAM are far less apparent ie there is little tangible value from higher speed RAM. I use 1600MHz RAM and do not see any microstutters or any other artefacts. I would set the RAM speed in the BIOS according to the specifications on the RAM and forget about overclocking it. There have been reports of various crashes where there is a mismatch between the fixed FSB and overclocked ram.RegardsPeterH

HEDThe main thing to remember about SandyBridge cpu's is that you are ONLY overclocking the CPU multiplier but the the Front Side Bus stays at the same rate so the benefits of faster RAM and overclocking RAM are far less apparent ie there is little tangible value from higher speed RAM. I use 1600MHz RAM and do not see any microstutters or any other artefacts. I would set the RAM speed in the BIOS according to the specifications on the RAM and forget about overclocking it. There have been reports of various crashes where there is a mismatch between the fixed FSB and overclocked ram.RegardsPeterH

I don't see any artifacts either. But it's impossible that you FSX is 100% smooth. Everyone must be seeing some very slight (I repeat very slight) hitching whenever you're below 40 fps.

Thank you guys; great info. Plenty of time left to make the exchange, albeit even more over-budget. Mike & John,My original reply would suggest still a bit of confusion on my part. But after re-reading your posts a bit more carefully this time, I understand what you were saying.

HEDThe main thing to remember about SandyBridge cpu's is that you are ONLY overclocking the CPU multiplier but the the Front Side Bus stays at the same rate so the benefits of faster RAM and overclocking RAM are far less apparent ie there is little tangible value from higher speed RAM. I use 1600MHz RAM and do not see any microstutters or any other artefacts. I would set the RAM speed in the BIOS according to the specifications on the RAM and forget about overclocking it. There have been reports of various crashes where there is a mismatch between the fixed FSB and overclocked ram.RegardsPeterH

Please excuses my slowness, but I'm still kind of foggy. The memory controller is built into the CPU and only recognizes 1066/1333, so if I install my new RAM (see sig), by default, it gets pushed down to 1333. If I change the BIOS to reflect the RAM's actual rated speed of 1600, wouldn't it still be pushed down by the CPU only recognizing it at a max of 1333?

HEDPlease excuses my slowness, but I'm still kind of foggy. The memory controller is built into the CPU and only recognizes 1066/1333, so if I install my new RAM (see sig), by default, it gets pushed down to 1333. If I change the BIOS to reflect the RAM's actual rated speed of 1600, wouldn't it still be pushed down by the CPU only recognizing it at a max of 1333?AFAIK the cpu recognises the faster RAM and is optimised for that speed but it doesn't mean that the transfer rate between the cpu and the RAM is significantly faster whether you have 1300Mhz or 2000MHz RAM installed, because the FSB is fixed. The difference AFAIK is that within the RAM itself with the higher rated RAM processing the working set faster and possibly smoother and then passing it back to the cpu. So there is a slight gain with higher speed RAM but not as significant as it would be if you overclocked the FSB as in the i7 9xxx series, but there is little point in oc the RAM in a SB cpu.If you look at many of the oc guides for the SB series the first thing that they get you to do is go into the BIOS and set the RAM speed down to the default 1300MHz and then once overclocked via the cpu multiplier you can then set the RAM to its "official" speed as stated on the RAM and set by the manufacturer plus the CAS latency settings if so desired.This explains it better than me: http://www.clunk.org.uk/forums/overclocking/39184-p67-sandy-bridge-overclocking-guide-beginners.htmlI hope that this is a little clearer?RegardsPeterH

That does help quite a bit, thank you.