Q6600/PC2 6400 RAM OC questions

[Airwik]

Hi all! To start off, I'm new to these forums and decided to join based on the raw amount of info I have learned just browsing around these boards reading this and that. This is a much more informative board than the others I was looking at. Anyways I have a few questions based on OC'ing a Q6600 and DDR2-800 RAM. I've been reading many guides lately on how to do this, and plan on trying a first attempt soon. I'm going to explain how I think it works and it would be great if you guys could read through it and correct my assumptions as you go along.

What I've gathered is CPU speed =CPUM(multiplier) x FSB. For the Q6600 its locked at 9x multipliers am I correct? and the Q6600 comes stock at 2.4 Ghz, so it would be 9x 266=2.4? So you just slowly increase your FSB by maybe a factor of 10-15 without increasing your Vcore until you become unstable with stress tests right? So now moving onto the RAM which I'm not sure I completely understand. How I think it works is if I have DDR2-800 ram you divide by 2 since its DDR2 so you get 800/2=400. Now most people try to get this 1:1 configuration with their CPU and ram or so I've read. So would this mean that the max I could OC my CPU to is 3.6 Ghz since 9x400=3.6 which would be 1:1 with the 400 I got with my ram?
Now lets say I wanted to OC my CPU to 3.0 which would be 9x333=3.0Ghz. Would it be a good idea or recommended to underclock my ram to 666 or whatever it would be to match that 1:1?
Last question would have to be about the FSB of the CPU. Now all guides called the number being multiplied by the CPUM the FSB, but on newegg it shows the FSB as 1066. What does this number mean and what roles does it play? I know motherboards mention this as well. In my mind it looks like theres two different kinds of FSB's or something. Confuses me Thx for reading.

 

[myocardia]

First, welcome to anandtech. To answer your questions,yes there are two kinds of FSB's: the real FSB, and Intel's pretend, inflated FSB (bigger numbers always equal higher performance, right?isgust. The real FSB on any Q6600 is 266 Mhz. And 9x333 Mhz FSB= a 3.0 Ghz Q6600. But why would you care if your RAM runs slightly slower than it's rated to run at? Do you play your television as loud as it will play any time you watch it? How about your stereo?

If you run RAM slower than it's rated speed, almost always you can then run it at tighter timings, which improves performance at least as much as running it at a faster speed. Also, with most decent motherboards, you can use a memory multiplier, which will allow you to raise your RAM's speed, whether you're overclocking the cpu or not.

 

[jeffw2767602]

you can run your ram at 667 3-3-3-8 (if you have good ram like crucial ballistix) or ddr1000 at 5-5-5-12....etc. the truth is you won't really notice a difference between ram running at higher speeds with higher latencies vs. low speed low latency. some people suggest that running ram at a 1:1 ratio improves stability but i am stable with 4:5, 5:6 and 2:3.

 

[Airwik]

alright I got it. Thx for the info! I thought it was kind of weird to under-clock the memory as well, but I read a few posts from people who I guess think its better somehow. Ill just be leaving the ram alone then I guess

 

[myocardia]

Well, if you aren't overclocking your cpu, then you can let the RAM run @ it's rated speed. You'll only get a ~1% performance boost, but that's not bad. But, that also assumes that you use the same timings at both speeds.

If you are able to lower the timings when running the RAM @ the slower speed, it usually more than makes up for running it slower. If you're overclocking your cpu, leave the RAM 1:1, so you can find out how fast your cpu will go. That way, you'll know for sure that it's the cpu that's keeping you from overclocking higher, and not the RAM. Make sense?

 

[wittangamo]

All good advice. Overclock the cpu first using 1:1 and conservative memory timings.

Once you've found a speed the cpu is comfortable with, you can play with the memory to squeeze out the last drop of performance.

For example, say you decide on 333x9=3.0ghz for the cpu. You can change the memory divider to 1:1.20. 333x1.20=400, so the ram is running at full spec.

A free benchmarking program like Sisoft Sandra will tell you how much bandwidth and latency you're getting at various settings so you can tell how much you gain or lose through timings and bus speed. Memtest will tell you whether a particular seting is stable.

If you'll post your full system specs, folks here can make suggestions about what might work. My rig is in my sig:

 

[Airwik]

well right now I'm typing this with my older comp. I ordered some new parts on the 10th, and I'm going to order the other half in nov so I can start building it then. It will include:
Abit P35-E
Q6600 (will make my first OC attemp)
OCZ DDR2-800 RAM
Foxconn 8800GTX factory OC'ed
Vista Home Premium 64-bit
OCZ StealthXStream 600W PSU

getting a Arctic Cooling Freezer 7 cooler for the CPU. It's cheap and I have read GREAT reviews on its performance.

 

[wittangamo]

Sounds like a nice system. Let us know how it works out.