Overclock advice wanted: Which first, multiplier or FSB?

AddRAM said:

Where is the front side bus readout for this motherboard ? Am I just missing it ?

1333 MHz ?

GIGABYTE - Motherboard - Socket 775 - GA-EP45-UD3R (rev. 1.1)

It's implied rather than directly shown. According to the motherboard manual, the CPU Host Frequency sets the FSB. For example, setting the CPU Host to 333 sets a FSB speed of 1333.

However, it looks like I've made some progress!

I set the CPU Host Frequency to 400 and the multiplier to 9.0 to get 3.6GHz. It just completed a 12 hour run of Prime95 without errors and with a max core temp of 61C.

Since I don't keep careful notes I'm not sure what is different between this time and the last time I tried.

Anyway, thanks a bunch to everyone for the help, looks like I may finally be on the right track.

OK, MCH frequency is the RAM spped. AKA the FSB strap.
At 400, this means the RAm is running at 800mhz before OCing. So the likely issue is that the RAM is running far to high. For now set your MCH freqto 333 or lower.

Under DRAM Timning, I would set it to run at 5-5-5-15 for now. Also, set the voltage at whatever is rtecommended. Once CPU is stable you'll be able to tweak here.

You may also wortk with the System memory mutiplier. This will change the FSB/strap.So that you can have says 400FSB (3.6) CPU OC, and get the RAM running faster or slower without changing the CPU clocks.

The reason you want the RAm underclocked is that when or if you get BSODS/failures, yit will be easier to find the problem.



CPU host Freq. is your FSB speed. I would set this at 400 for now, with a CPU multi of x9 (3.6Ghz clock speed)
The lower FSB will still be a overall improvement, with faster CPU speeds. But also,, the RAM will not be clocked as high, and should ... overall be more stable as less stress on the NB.
You should be running stable this way with a Vcore on the CPU of around 1.25-1.28 with that chip (ballpark, off the top of my head)



---EDIT --- missed your last post ...

Difference, may just be that the FSB is more stable there? Or higher FSB pushed the RAM beyond its ability causing issues.
Honestly, its hard to say as every setup is different. Even identical ones. I had a Core2 Duo that would run happy at 3.6. At 37-3.8 ... nothing seemed to get it stable. Push the FSB up, and BAM 4.0 no issue (though far more more heat & juice than I wanted 24/7).

Point is, Some are just wierd, some OC like champs ... others dont want to be messed with after a certain point. Just takes time and patience to find your setups personality and sweet spots :)