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NB Voltage and overclocking to 3.8ghz

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ZealEngine

Registered
Joined
Dec 6, 2009
I have the following setup...

Asus M4A79XTD MB
AMD PH II X4 955 3.2ghz BE
Sunbeam freezer with AS5
Saphire Radeon 4890
4gb Gskill PC 1600 DDR3
2x 1 TB Seagate HD (Raid 1)
Antec 300 case with extra fans (all air exiting the case is cool)
500w Thermaltake psu

After much research, I have been able to get a stable overclock of 200 x17 (2200 HT, 2200 NB) at 1.4v cpu, 1.175 cpu/nb (stable prime 95 for hours, max load 52c). However, if I push much beyond that, I prime95 usually wont last longer than a few minutes.

My question is, I have read Dolks research, and I know he suggests I should be running between 1.175-1.25v for my cpu/nb, but the problem is my bios has THREE "NB voltage settings", they are...

CPU/NB Volt
NB Volt
NB 1.8 Volt

Assuming I am aiming for a 3.8ghz overclock, can anyone tell me what THOSE THREE voltages should be? I also imagine I might need to bump up my cpu voltage higher than 1.4v, but I have heard people say they get to 3.8 stable at 1.4 by only bumping their NB voltage...

*BTW do my ram settings matter when overclocking? I am currently 1600hz at 1.5v 9-9-9-24 timings.

Thanks in advance!
 

Parad0x420

Member
Joined
Jun 22, 2007
Location
Dark Side of the Moon
I have my CPU/NB voltage at 1.2625v, NB set at 1.10v, and NB 1.8 @ 1.80v. As far as other voltages I've manually set, CPU VDDA 2.6v, RAM 1.8v (its what my Dominators want), HT 1.20v and SB 1.20v. I don't like leaving these settings on 'Auto'. The voltage you want to change regarding your NB speed is CPU/NB. My NB is @ 2400mhz using 1.2625v. I haven't tried pushing my chip much further than 3.7, I was satisfied with that for a while. Your RAM speeds may matter if you decide to bus clock, cause it will increase them past 1600mhz.. I've heard the AM3 seems to have trouble OC'ing DDR3 much past 1700mhz.
 
OP
Z

ZealEngine

Registered
Joined
Dec 6, 2009
Interesting.. so you left your "NB Volt" and "NB 1.8v" at defaults, and only had to bump your cpu/nb volt... I will give that a try later today.

I've manually set, CPU VDDA 2.6v

Hmm thats the first time ive heard anyone mention that one... What exactly does it do again?
 

Parad0x420

Member
Joined
Jun 22, 2007
Location
Dark Side of the Moon
I'm not sure what it does, BUT when Dolk originally started writing his guide VDDA voltage came into question. I did a little reading around and found a few people who suggested bumping it up one notch from default. Default on my system was 2.5v, so I bumped it to 2.6v, and I think Dolk has mentioned somewhere to bump it up to 2.6 too.