Why is OC successful on 3 Cores and not 4 cores?

[alexpho]

Ok, I've been trying and trying to OC successfully beyond 3.8 on all 4 cores. I use Prime to test my results. I gave up on any software OCing and just strictly BIOS.

So if any of you reading is on an ASUS M4A87TD EVO motherboard and AMD 965 BE, please send me your settings if you have successfully gone over 4 ghz stable. These are what I have.

After tweaking and tweaking, I winded up with 3.9 stable. But the strange part is, I realized that only 3 cores were " ON ". So on the next restart, I changed in Bios to 4 cores while keeping the same settings. I run Prime again, and it failed.

My question is... why is that and what does it mean? Does it also mean that getting 3.9 on three cores is the same performance and 3.9 on 4 cores?

NB-2600
volts- 1.45
HT- 2000
RAM- 1533
CPU multi- 17
cpu freq - 232

Everything else at auto.

Thanks for your time.

 

[henydiah]

My question is... why is that and what does it mean?
Does it also mean that getting 3.9 on three cores is
the same performance and 3.9 on 4 cores?

- so your oc not stable and need more tweak, maybe voltage, timing or other setting by disabled/enabled
- 3core at 3.9Ghz will slower than 4core 3.9Ghz
You can compare both use cinebench 11.5
- everything else auto . ? What auto cnq/C1E/spread spectrum

 

[lowjack989]

You disabled cores on an X4???????????......Why?????......All you need to do is up the voltage on the core a bit.....Your logic befuddles me

 

[alexpho]

I stumbled on 3 cores because the MB defaulted to 3 during all those restarts. So when it was Prime95 and passed I was happy, until I realized it was only on 3. Of course I want to go with 4 cores.

I'll tweak again. Thanks

 

[lowjack989]

When running prime95 ...if one core shuts down then it is a BAD OC....If your board disabled a core on restart from an OC failure IMO...I would RMA that MOBO faster than you can say "RMA"...I doubt the latter is the case though

 

[lowjack989]

NB-2600
volts- 1.45
HT- 2000
RAM- 1533
CPU multi- 17
cpu freq - 232

Everything else at auto.

Thanks for your time.

Your NB voltage is 1.45v?...J/K I know its your vcore... Why not just set your FSB to 200, DRAM to 1600, Multi. x20, CPU vcore--->start at that 1.45v and go up from there until stability is achieved.....DO NOT SET THE VCORE ABOVE 1.55v EVER!!!!!!!...NB 2600 MHz@1.2v...My 965BE got stable at 1.488v@4.0GHz

 

[ahthurungnone]

The problem is that you are trying to reach 4.0Ghz by upping the frequency of the entire mobo instead of just the cpu multiplier. This affects your NB, RAM and your GPU which typically leads to crashes. You would be better off to drop the NB frequency to 200Mhz, set the RAM timings to the stock settings and voltage (on 2T of course) and just up the multiplier to 20x. This way the ram can run at stock settings of 1333Mhz (the sweet spot for ram). Most RAM doesn't maintain 1600Mhz very well and you can't tell any performance difference. The faster the cpu processes the data the faster it utilizes the ram. There seems to be a positive correlation between cpu and ram speed.

And if you still get a BSOD during Prime95 you just slowly up the Core (cpu) voltage, but you are already very high in my opinion. Keep an eye on the core temp when running Prime95. You should never get near 50C at full load or you need a better cooler.