New Build: i7 930 and Memory Frequencies

[5R0]

So my P5K Premium / Q6600 combo finally died on me the other day, and I've been looking for a new setup; things appear to have changed a LOT in the last three years, so I have a few general questions about the build I'm considering and how to get the better performance out of everything.

Specs I'm looking at are:
i7 930
ASUS P6X58D Premium
12gb DDR3 1600 (6x2GB, haven't decided on a brand yet, opinions welcome)
Corsair 850TX

On to the questions:

1) Is there a big difference in what multiplier I use. I'm looking for speeds in the 3.4GHz range, so the obvious setup is something like 17x200. The question is, would it be better in some way to use something like 21x166 instead? I seem to remember that higher FSB speeds result in higher voltage requirements and thus higher temperatures, but I don't know if this applies to the current generation.

2) Can somebody explain how memory frequencies work. My old rig ran a Q6600 @ 8x200, with 4GB of DDR2 800, and everything seemed to work correctly, but now we're into triple channel memory and I don't even know where to begin. This ties into question 1, because my goal is to set the FSB frequency to something that will compliment the DDR3 1600 memory. Comments are really appreciated here, and if you can explain how to calculate this number, I would appreciate that as well.

3) What kinds of temps can I expect with stock cooling at ~3.4GHz? I'm probably going to go for aftermarket cooling even without an O.C., but it would be nice to know what to expect.

4) Are there any other numbers I'm going to have to worry about? I've been hearing about something called QPI now that has to be adjusted as well as FSB, but I have no idea how the two are related.

Sorry if I've left anything out. Due to the extreme number of processors available now and the hundreds of different configurations that have been accomplished, it's hard to find relevant information.

Thanks in advance for your help. Please let me know if additional information is required.

 

[coffeejunkee]

2) Nothing really changed, except ratio is called multiplier now. Standard multiplier is x8 which makes 133x8 = 1066MHz. If you want to stick to the x8 multiplier you need 1066 for bclk 133, 1333 for 166 and 1600 for 200.

Keep in mind that standard voltage for ddr3 modules is 1.5V. Every module that needs more than that is in fact overclocked (although the manufacturer guarantees the rated speeds). If choosing this kind of memory I would definately go for 1.65V memory modules instead of older ones that are still around and need 1.7-1.9 to reach their overclocked speeds.

 

[5R0]

Thanks for the prompt reply. So if I understand correctly, DDR3 1600 will work correctly with a FSB speed of 200MHz in triple channel mode?

Is there a disadvantage for running the i7-930 at 17x200 to synchronize it with the RAM then? This is probably the route that I'll take if possible, as I don't want to place an extreme amount of strain on the components.

 

[coffeejunkee]

Yes, bclk 200 works correctly with 1600MHz ram. Triple channel doesnt really have anything to do with this, it's the same for dual. But I'm not sure it's that big of a deal anymore, Lynnfield fex. uses x10 multiplier (so 1333MHz standard). To run really high-speed ram like 2500MHz you'll probably need the x12 multiplier.

Your other questions would likely be better answered by Bloomfield users. My experience is that it doesn't really matter that much. Without benchmarks I couldnt tell if I was running 200x20 with 1600MHz or 1200MHz memory. I would pick the multiplier/bclk combination that gives the highest cpu freq with least voltage and match memspeed to that.

In general, 200x17 shouldn't be an issue at all, as long as you have good cooling. As opposed to 166x21 you'll probably need a bit more voltage on the memory controller. But I wouldn't call it extreme stress. Budgetwise you'll be better of with 166x21 running 1333MHz memory. But you'll be dreaming of that sweet x8 multiplier when you do decide to overclock further. Or just overclock your 1333MHz ram, see how far it'll get on 1.65V.