FX-8120 temps

[ssjwizard]

100 points is pretty much inside the margin for error. You should be running your HT link at 2600 anyways since thats what the CPU is designed for. HT link speed effects how much bandwidth you have to your PCI-E slots (and every thing else) while the CPU-NB has to do with memory access. Ive not have the greatest results from overclocking the CPU-NB on these chips(stability issues) but it certianly can make a difference in a benchmark when your looking for every last point.

 

[Joni]

100 points is pretty much inside the margin for error. You should be running your HT link at 2600 anyways since thats what the CPU is designed for. HT link speed effects how much bandwidth you have to your PCI-E slots (and every thing else) while the CPU-NB has to do with memory access. Ive not have the greatest results from overclocking the CPU-NB on these chips(stability issues) but it certianly can make a difference in a benchmark when your looking for every last point.

Are you sure HT link is 2600? CPU world says it's 2600, Asus boards have set it default as 2200 and some sources say 8120 has 2200 HT link speed.

 

[Joni]

I'm also little confused about the NB voltages, when trying to get NB stable at 2600 MHz, should I adjust the CPU/NB voltage which is 1.45 V at stock settings or NB voltage that is 1.1 V at stock?

 

[ssjwizard]

The 1.1v one, I run mine at +75 on gigabyte bios, but 1.25v is generally the voltage I hear recommended by people with asus/asrock boards.

 

[Joni]

Sorry the CPU/NB voltage was 1.25v on default. So NB frequency in the BIOS is NB on the motherboard, not CPU NB?

 

[Joni]

I figured out the NB voltages on Asus BIOS. Only thing that puzzles me is that are these voltages safe for NB?

On default NB voltage setting (auto) NB 2.2 GHz has 1.212 V, if I change NB to 2.6 GHz BIOS sets NB voltage to 1.45, that seems quite high compared to what people have suggested using.

I also tried to manually set the NB voltage and it indeed needs minimum 1.45 at 2.6 GHz to be stable on Prime.

Also if 8120 has HT 2600 why is it set as 2200 by default on Asus motherboards? Or is it just that it needs to be less or equal to NB?

 

[BeerCzar]

I followed the guide listed below to get my 8120 OC'd to 4.5ghz at 1.35v. After tweaking the Voltage i found for 4.5ghz 1.35v is the lowest you can go.

I ran Prime 95 for about 8 hours with no failures, and with CPUID Hardware Monitor my CPU hit 61c but my 8 cores never broke 54c over that 8 hour period. Stable as can be. Even when playing games the past few days the cores don't get past 45c and I have new fans and thermal paste coming in to give it better airflow... oh the link below is great btw.

http://www.overclockers.com/forums/showthread.php?t=688663&highlight=STEVENB

 

[Joni]

I followed the guide listed below to get my 8120 OC'd to 4.5ghz at 1.35v. After tweaking the Voltage i found for 4.5ghz 1.35v is the lowest you can go.

I ran Prime 95 for about 8 hours with no failures, and with CPUID Hardware Monitor my CPU hit 61c but my 8 cores never broke 54c over that 8 hour period. Stable as can be. Even when playing games the past few days the cores don't get past 45c and I have new fans and thermal paste coming in to give it better airflow... oh the link below is great btw.

http://www.overclockers.com/forums/showthread.php?t=688663&highlight=STEVENB

Did you used LLC? I got stable 4.4 GHz @ 1.320 V with LLC.

I'm running at 4.2 GHz now since I got it stable at as low as 1.260 V. I'm able to turn all my fans to lowest (750-900 rpm) and still have some room for temps, also Geekbench 11391 and Cinebench 6.92 is really nice improvement

Anyone know anything about that CPU/NB voltage on new Asus boards, if I raise CPU/NB to 2400 MHz, auto voltage setting raises the voltage to 1.40 V and raising it to 2600 MHz it goes to 1.450 V. Aren't these a bit high for CPU/NB?

 

[trents]

Joni, it might help if you take a digital camera pic of the relevant sections of the bios that deal with the places "NB" is found. It can be very confusing when trying to sort out the chipset NB from the CPUNB. Generally, the CPUNB is found in the same section as the other CPU adjustments and the chipset NB is found in the same section as the SB stuff.

 

[Joni]

Found these from google images. I was talking about "CPU/NB frequency" and "CPU/NB voltage". When changing "CPU/NB frequency" to 2400 MHz "CPU/NB voltage" jumps to 1.40 V with default auto setting, when 2600 MHz voltage jumps to 1.45 V. I tried to manually adjust the "CPU/NB voltage" but 2400 MHz wasn't stable below 1.40, even on CPU at stock settings.

For some reason it requires this much voltage, alot more than what I've seen others having, so I'm wondering if these are safe voltages to use? Default voltage at 2200 MHz i think was about 1.2X V

 

[trents]

Disable the Load Line Calibration enabled for the CPUNB set it manually to the desired level, which is about 1.225 for that CPU in my experience.

 

[Joni]

Disable the Load Line Calibration enabled for the CPUNB set it manually to the desired level, which is about 1.225 for that CPU in my experience.

LLC for CPU/NB is disabled. Did you mean setting it to high or leaving it disabled and manually adjusting the voltage?

 

[trents]

Set the CPU/NB voltage manually to 1.225 and leave its LLC disabled.

 

[Joni]

Thank you it worked! That was actually the first thing I tried yesterday but I guess I must have set the CPU/NB LLC to auto when I meant to disable it :/

 

[trents]

I have that same board but the non-evo version. I found out right away when the CPU/NB LLC was set to Auto the system was very unstable. Yet, it seemed to benefit from leaving the main CPU LLC on Auto. I also found that if I put the manual CPU/NB voltage higher than 1.235 it started to show instability again.

 

[trents]

I also find to giving the ram a small bump in voltage over stock can help with stability, even though the ram is not actually being overclocked. Like if stock is 1.5v bump it up to 1.525 or 1.55. And those 960T CPUs like to have a little bump given to the HT Link frequency, like from 2000 mhz to 2200 mhz (but no HT voltage increase) and also to the CPU/NB frequency, say from 2000 to 2600 mhz.

 

[Joni]

Thx, ill try that

 

[Joni]

2400 MHz CPU/NB is stable with default voltage about 1.212 V, for some reason 2600 MHz isn't stable even on 1.30 V, I guess the problem is somewhere else than CPU/NB voltage, like in RAM voltage like you said before.

Also one thing I'm wondering about LLC.

I was able to get 4.2 GHz at 1.260 V with LLC at 75%. CPU-Z and HWMonitor shows voltage is stable 1.260 V in all scenarios I've tested. I was wondering if it's better to use LLC at 75% considering that there are no funny voltage increases or set LLC to lower value and set voltage little higher like 1.280 so that it's 1.260 in stress because of vdroop? I mean do I actually benefit from constant 1.260 vs the 1.260-1.280, or is there some negative effect in LLC itself that I'm unaware of, for example that it creates heat only by trying to keep the constant stable voltage or something?

 

[trents]

It would be good to experiment with different LLC settings. The only thing you have to watch for is choosing a setting that gives dangerously high CPU voltage under load. Your CPU voltage in the 1.26-1.28 range is still very low. As long as core and CPU temps remain under control you can go much higher than that, I mean up into the mid 1.3's anyway.

 

[caddi daddi]

+1, trents, 4.5 and above all my 8120's need 1.5+volts and scale to the limit of 1.55 volts under llc at 4.8.
+2 trents, i have installed a fan on my case to cool the backside of my socket and this keeps my socket temps down and I have also found that it reduces my core temps some.

if you can get to 4.9 or above 8 hours prime 95 stable, please let me know as I have yet to get beyond 6 hours. and very shot runs at 5.0 even overvolting.