Help OCing E8500 (Voltages and RAM)

Hi all, I'm aware that this is a subject that is around all over the place, though I've spent several hours today looking for help and would like some clarification as I'm a little nervous about overclocking. Plus I've fried my brain a little with all the terminology!

My system is as follows:

E8500 (already overclocked to 3.8GHz)
Gigabyte EP45-DS5 Mobo
4GB OCZ DDR2 (full specs on exact memory here)
EVGA GTX 280 factory overclocked
Ultra 120 Extreme (AS5 paste) with a 2000RPM Sharkoon 120mm on it, + 3 others on front, side and back of an Eclipse62 case.
XP 32 bit

I've already overclocked from 3.16 >> 3.80, just by upping the FSB to 400mhz with a multiplier of 9.5, and setting the Vcore to 1.3V. My first question involves this voltage; it's the ONLY voltage i have explicitly set in the BIOS so far, and CPUZ shows a 'Core Voltage' of 1.280V. Why the disparity here? I appreciate it's only .02 of a volt, but it's quite a difference since we're talking about small numbers in the first place!

I'd like to get a stable 4.0+GHz overclock for running Flight sim X - i'm aware that the safest way to do this would be to notch up the FSB, while slowly increasing the Vcore to get stability. What other voltages do I need to adjust? What about RAM? My ram timings should be 5-5-5-18, and CPUZ shows them as such at the moment with a 1:1 DRAM ratio. Will the timings remain as that so long as I keep the ratio 1:1? Even though the timings SEEM to be correct on auto settings, I tried setting them manually today and was greeted with a blue screen upon trying to boot XP.

I'm aware that the FSB x memory multiplier = memory frequency. CPUZ tells me that my 'DRAM Frequency' is 400MHz, but the BIOS marks the 'Memory Frequency' as 800MHz. What is the difference between these two? I at least inferred that my FSB x multi of 2 gives 800MHz which matches this number in the BIOS, and thus registered a FSB : DRAM ratio of 1:1 in CPUZ, but I'm unsure of what to do with all these numbers after a further overclock. I'd never thought of any of this when I pushed it initially up to 3.8GHz a few months ago!

A further element of confusion is the G(MCH) Frequency latch, which I've set manually to 400MHz, and a multiplier of 2.00D, the lowest available for that latch (and giving the right ratio). My memory will apparently run at 1000MHz; would it be better to keep the 1:1 ratio or to sacrifice it for the faster 1000MHz?

I can take photos of the BIOS if that would help anyone, I'm just looking for help overclocking safely as high as I can get. FSX is a very CPU intensive app, and sends even the best i7s to 100%!

Thanks for your time!

The difference in voltage is due to Vdroop which comes on every board, it comes with the territory.

400 is actual memory frequency, 800 is effective.
You may want to add some memory volts and tighten its timings.
You would also need to increase nb voltages if you want to tighten timings.

Quote:

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Originally Posted by Blaineoliver

You may want to add some memory volts and tighten its timings.

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So that'd just be increasing the DRAM Voltage? Have you any idea how much by? Which timings in particular should I tighten? CAS, tRDC, tRP or tRAS?

Quote:

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Originally Posted by Blaineoliver

You would also need to increase nb voltages if you want to tighten timings.

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Again, how much by? I don't have any aftermarket cooling on my nb, would this be safe?

Cheers for the help :)

Yea some more info would be helpful for a comp im playing with at the moment. Or a guide would be much appreciated.