FX 8350 Brick wall

[cadaveca]

I find that very unlikely. Raja from Asus ROG tech support who is the absolute guru on Crosshair motherboards said 1.30 volts is the limit for cpu-nb. Of course this guy has a Sabertooth but it is the same chipset and mosty likely the same settings limits as Crosshairs. I have never set my CPU-NB clock that low and I have never fried my chip.

Piledriver or Vishera, is not like other FX chips, or Phenom X6 or X4. NB speed cannot be set independently like those chips, and this time is directly related to memory speed.

The CPU-NB, up to 1.3 V is fine, sure, but you should not NEED to increase CPU-NB at all, all the way up to 2666 MHz memory(I am not sure on higher since my memory does not go higher).

AMD says :



1. Set the CPU Water-cooler fan speed to “Extreme” (if not already) to maximize the cooling using your latest ASUS bios, try the following BIOS settings:

 Disable APM_Master_En (disables APM which may cause the CPU to throttle at full load) 

Disable Turbo Core  go to the ASUS VRM settings and adjust everything to the max (I.e: use “High” for CPU Load Line calibration and disable Overcurrent / Thermal protections) – NOTE: you might want to have an extra fan on top of the board to ensure the VRM heatsink doesn’t get too hot. 

2. try CPU voltage values between 1.40…1.55V and find the optimal setting – if the board just shuts down during full load it means it hit OCP limit (this seems to happen once the CPU pulls more than 26.5A from the 12V CPU rails (8pin and 4pin connectors). You’ve hit the OCP limit and should decrease the voltage a bit. When using the “High” setting for load line calibration the board should not reach the current protection limit that easily 

3. CPU NB Voltage can remain at default (or you could adjust it if it seems to improve things – we were able to hold it at default to run at 5.0GHz) 

4. Try a few more CPUs (if available) – you could see 100-300MHz delta going from one CPU to another 
Try disabling cores: o disable cores 1,3,5 and 7 for optimal performance (Cores 0,2,4 and 6 remain active => 4CU/4cores active) o disable cores 4,5,6 and 7 for optimal OC (Cores 0,1,2 and 3 remain active => 2CU/4cores active) 
5. Ensure that the thermal contact between the CPU and the watercooler is optimal – use high quality thermal paste

6. Use the ASUS Monitoring software to keep track of actual CPU Voltage and CPU Temperature

 

[os2wiz]

Piledriver or Vishera, is not like other FX chips, or Phenom X6 or X4. NB speed cannot be set independently like those chips, and this time is directly related to memory speed.

The CPU-NB, up to 1.3 V is fine, sure, but you should not NEED to increase CPU-NB at all, all the way up to 2666 MHz memory(I am not sure on higher since my memory does not go higher).

AMD says :

Very interesting. I had not realized that the Vishera overclocking criteria were so different. ASUS really hasn't said a lot about it at all. Good thing you picked up those criteria from AMD.
That what I like about these forums here. WE have some very inquisitive members here who browse everytrhing they can get their hands on . You are a good teacher. We all can learn, especially myself.

 

[cadaveca]

Memory controller is now fully 128-bit, hence the major difference. Previous chipshad dual 64-bit memory controller (that could be "ganged" together as 128-bit controller, or "unganged" as dual 64-bit) on 128-bit bus. Independent NB speed helped adjust for dual controllers, it seems, while with a singular 128-bit controller, it's best to adjust NB speed according to memory speed, so that the controller matches memory in the most optimal way.

At least, that's how I understand it. That change is why the controller is more efficient than Bulldozer, I imagine?