Hi friends. I tried undervolting my Phenom II x4 955 from 1.35v to 1.20v and all normal tasks are handled fine. However, when I started Far Cry 3, the game kept crashing with blue screen and PC restarted every single time on it. Does voltage of CPU have a direct bearing on gaming? Is it that games require CPU voltage to be higher than a certain degree?
Tweaking the voltage can adversly affect stability. If your undervolt is stable, then it will have zero affect in gaming. However, it sounds like you have an unstable undervolt. Use Prime95 to test stability. Most unstable settings will fail within the first hour, but for maximum stability run for at least 24 hours or more (I normally do 32 hours). If it runs that long without error, then it's perfectly stable.
It sounds like your undervolt is failing under heavy load (Farcry 3). As the other poster suggested, you should Prime95 to see just how bad things are. From there bump up the voltage little by little until stability is achieved.
Why are you undervolting to start with? Temperature issues?
Yes. I don't want this phenom ii x4 955 to cross 55c under any circumstance. I am soon going to get a new cpu cooler. But I'd still prefer undervolting a little bit so temps don't go as high as without an undervolt, even under load. This stock cooler of AMD is annoyingly loud and reaches 5300+ RPM under load.
Of course voltage affects the chip's stability. If you demand 55c ror less, and have reduced the voltage to achieve this, you'll likely need to reduce the clock as well. If the CPU would have run properly at 1.2v, AMD would have sold it that way.
Of course voltage affects the chip's stability. If you demand 55c ror less, and have reduced the voltage to achieve this, you'll likely need to reduce the clock as well. If the CPU would have run properly at 1.2v, AMD would have sold it that way.
Not all chips are made equally. AMD (and Intel) chooses a voltage that allows them to use the most amount of chips without excessive temperatures or power consumption. Often times, the voltages selected are a bit high for most chips manufactured.
Yes. I don't want this phenom ii x4 955 to cross 55c under any circumstance. I am soon going to get a new cpu cooler. But I'd still prefer undervolting a little bit so temps don't go as high as without an undervolt, even under load. This stock cooler of AMD is annoyingly loud and reaches 5300+ RPM under load.
I find the stock cooler perfectly acceptable at ~2000-2400RPM (25-34%). I'd lock it there in the BIOS (or at whatever level you find acceptable), and use prime95 (in-place Large FFT test) to see what kind of temps you get. Adjust clocks/voltages accordingly and use Prime95 again for stability testing (either small FFT or Blend).
Bear in mind that Prime95 will put a load that the CPU will almost never in real life.
You're sure jerm? I mean, I remember someone saying that 61c is threshold for this CPU. And if it is already crossing 55c on load in a game, won't it reach beyond 60c with prime95?
62c is the maximum recommended temperature. Going a little above that for a short period of time won't kill the CPU, but prolonged periods of time above 62 will likely shorten the life of the CPU. Different games stress the CPU differently, and most do not fully utilize multi-core CPUs. Not much of a benchmark for thermals. If you decide to play a new game for hours and it just so happens fully utilize the CPU, pushing temps above 62c, when your other GPU bound games only push the CPU to 55c... well, that can be problematic. This is why Prime95 is much better for testing thermals. If prime95 can't push the CPU beyond 62c, you can rest assured that no game ever, even its wildest dreams, will ever cause your CPU to overheat.
There are failsafes as well. So if you decide to go out for pizza and beer during a torture test in the middle a hot afternoon instead of monitoring your temperatures like one is suppose to, modern CPU's will throttle before it gets to the point of permanent damage. You can also set themral cut offs using a temperature monitoring program, such as CoreTemp, which can execute a certain commands once a thermal threshold is crossed, such as put the computer to sleep, or shutdown.
So run Prime95, large FFT, for about 15-20 minutes. You should get maximum temperature by then. Monitor your temps during the test. If you notice the temps exceeding 62c, you can stop the test. Adjust settings. Rinse, repeat.
Undervolting your CPU doesn't damage it. Inside your CPU there are transistors organized in logical circuits and data storage circuit. Varying on design your CPU will turn some of these circuits off if they are not needed or lowering the clock cycle to use less energy. When you load a game or another processing intensive program.
The CPU prefetch a lot of data into the data storage/cache circuit for fast computation (since it is way faster than your RAM or your harddisk), and executes these commands and storing data. Thereby you are activating all the circuits in your CPU.
Thereby consuming a lot of energy some of that is lost inside the transistors as heat along the way. When you have a lot of transistors to go through you there may be not enough energy to switch the last of your transistors resulting in internal errors (like computational errors and program count errors).
The damage is not on the cpu, but can result in corrupted data in RAM and harddisk. Mishandling of hardware interrupts and so on. So don't undervoltage your CPU unless absolutely necessary ( or don't do processing intensive tasks you decide.)
Running at high... out of recommended specification temperatures CAN lead to transistors being overheated, which will result in a short circuit, burning the transistors inside. But better wait and get a better cooler it is way cheaper in the long run.
I bought a new cooler and I don't undervolt below 1.25v now as I don't need to. Thank you everyone :) I couldn't think of running prime95 with stock cooler. That thing is not only loud, it's inefficient with temps going upwards of 57 just on gaming load.
Glad everything worked out!