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X2 555 BE Advice Needed

post #1 of 5
Thread Starter 
Hi, I'm pretty much a beginner to overclocking, hadn't looked into it at all before a week ago, but picking it up pretty fast.

I've got the Phenom II X2 555 BE and I've successfully unlocked to 4 cores (ran prime95 for 12 hours on stock values with no errors). The rest of my system is in my signature.

I've been experimenting by playing with the ref. clock, the cpu multiplier, the NB multiplier, chipset voltage, cpu voltage and the memory frequency to see how far I can push. I've managed to get to 3.8GHz stable, but beyond there I hit trouble. I can get 3.9GHz to work (ish), but it fails after 2-3 hours of Prime95 torture testing. If I try going to 4GHz it fails within 15 mins of Prime95. And by fail I mean either BSOD or system just shuts off and reboots

I've basically been fiddling around going by the 2 rules of keep cpu temp below 55 degrees and keep voltages below 1.5V.

I've also found I've had more success keeping the ref. clock at stock and raising the cpu multiplier lots, rather than raising ref. clock and only slightly adjusting cpu multiplier. This is presumably due to my bog standard RAM which can't handle being pushed much at all.

I was wondering if anyone could give any advice, particularly if they have experience OCing either the X2 555 BE unlocked to 4 cores, or this motherboard. I was especially wondering whether a PSU upgrade or better RAM would be more useful (I can't afford both).




In particular, a couple of results mystified me:

With the ref. clock set to 200 (stock) and VCore set to 1.55V (that's the value I set in BIOS, according to Speedfan and ASUS Probe, it was actually bouncing between 1.47V and 1.5V) I could get 3.9GHz to pass 30 mins of Prime95 with

a) NB multiplier set to x10, RAM freq set to 533mhz
b) NB multiplier set to x8, RAM freq set to 667 mhz

but I could NOT get it to pass more than 5 mins of Prime95 if I tried to combine a) and b) ie. NB multiplier set to x10 and RAm freq set to 667mhz.

Intriguingly (at least to me), if I set Chipset Voltage to 1.31V ( I *think* the stock is 1.2V but I'm not sure), then it *could* pass half an hour of Prime95 with NB x10, 667mhz RAM and 3.9GHz CPU, and was wondering exacty what difference that voltage was making. I couldn't quite make out in BIOS if that was the NB voltage, my BIOS didn't have an obvious NB option; there was either chipset or VDDNB voltages.
Edited by Darkshine - 12/27/10 at 5:31pm
post #2 of 5
Ok. Here the breakdown on that you need to know for ocing any athlon II and phenom II cpu on air.
1) Max cpu voltage is 1.55v.
2) Keep temp under 55c.
3) NB frequency take it as high as you can take it and stable.
4) CPU/NB voltage max 1.45v. This the voltage for NB Frequency.
5) Keep HT around 2000.
6) Keep memory close or under to stock speed.
HTPC
(11 items)
 
  
CPUMotherboardRAMHard Drive
AMD A-3870K AsRock A75 Pro (FM1) HyperX DDR3 1866 8 GB SAMSUNG 830 256gb 
Hard DriveOptical DriveCoolingOS
SAMSUNG EcoGreen F4 2TB Plextor Black Blu-ray Burner Phenom II X4 stock Cooler Windows 10 
MonitorPowerCase
LG M2762D-PM Glossy Black 27" 5ms (1920x1080) Antec HG 900 Gerenic ATX Case 
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HTPC
(11 items)
 
  
CPUMotherboardRAMHard Drive
AMD A-3870K AsRock A75 Pro (FM1) HyperX DDR3 1866 8 GB SAMSUNG 830 256gb 
Hard DriveOptical DriveCoolingOS
SAMSUNG EcoGreen F4 2TB Plextor Black Blu-ray Burner Phenom II X4 stock Cooler Windows 10 
MonitorPowerCase
LG M2762D-PM Glossy Black 27" 5ms (1920x1080) Antec HG 900 Gerenic ATX Case 
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post #3 of 5
Thread Starter 
Having played around some more, my problem appears to be Vdroop.

Running with ref. clock, HTLink and RAM at stock vaues, CPU/NB slightly overvolted and slightly overclocked, and multiplier putting CPU at 3.9 or 4 GHz, HWMonitor is showing my Vcore mostly holding to the set value of 1.525V, but there are very rare half second spikes in the 1.6-1.7V range, and more common 3-4 second drops in voltage down to 1.1V. I think it's those drops that are causing failures in Prime95. Temperatures at load are usually about 50, and never go above 55.

I've experimented with Load Line Calibration from 0% to 50% and Vcore from 1.5V to 1.55V to try and get a stable vcore in the 1.5V to 1.55V range, which I believe is what I need to run this CPU above 3.9GHz, but I can't seem to avoid those spikes and drops.

I'm not too worried about the spikes as they're very very rare and never last more than half a second, and I read an article saying that CPUID has a tendency to overestimate voltages on this motherboard.. But dropping down to 1.1V for more than a couple of seconds can't be ignored as an error, and is surely going to cause my CPU problems at more than 3.8GHz.

Anyone have any suggestions?
Edited by Darkshine - 12/28/10 at 9:31am
post #4 of 5
Disable CE1 and cool & quiet.
Edited by dixson01974 - 12/28/10 at 6:22pm
HTPC
(11 items)
 
  
CPUMotherboardRAMHard Drive
AMD A-3870K AsRock A75 Pro (FM1) HyperX DDR3 1866 8 GB SAMSUNG 830 256gb 
Hard DriveOptical DriveCoolingOS
SAMSUNG EcoGreen F4 2TB Plextor Black Blu-ray Burner Phenom II X4 stock Cooler Windows 10 
MonitorPowerCase
LG M2762D-PM Glossy Black 27" 5ms (1920x1080) Antec HG 900 Gerenic ATX Case 
  hide details  
Reply
HTPC
(11 items)
 
  
CPUMotherboardRAMHard Drive
AMD A-3870K AsRock A75 Pro (FM1) HyperX DDR3 1866 8 GB SAMSUNG 830 256gb 
Hard DriveOptical DriveCoolingOS
SAMSUNG EcoGreen F4 2TB Plextor Black Blu-ray Burner Phenom II X4 stock Cooler Windows 10 
MonitorPowerCase
LG M2762D-PM Glossy Black 27" 5ms (1920x1080) Antec HG 900 Gerenic ATX Case 
  hide details  
Reply
post #5 of 5
Thread Starter 
Already had them off.
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