Prime95 crashing PC.

[Stellarisk]

I ran prime95’s blend mode after installing my pc in its new case and after 6 minutes after it said something about doing a continuous test before freezing at 66 temp. I then ran the small test and it freezes after 1-2 minutes followed by a bsod that followed whea uncontrollable error. It did not leave a crash dump. Is my pc broken? As far as I can tell it doesn’t crash me while playing an intensive game. I have an i7 8700 which vcore I have set to 1.2

[Bitter]

Something is unstable, probably the CPU if it failed a small test. Set it all back to original settings and try again. Crashing out so fast usually happens when somethings volts are set too low, overclock too high, or maybe really unstable power delivery to the CPU.

[Kilrah]

9 minutes ago, Stellarisk said:

which vcore I have set to 1.2

Probably too low, just set back to default.

[Stellarisk]

1 minute ago, Bitter said:

Something is unstable, probably the CPU if it failed a small test. Set it all back to original settings and try again. Crashing out so fast usually happens when somethings volts are set too low, overclock too high, or maybe really unstable power delivery to the CPU.

See I had originally had it on auto.  But  it was going crazy with the heat and I was recommended to manually set the vcore over letting the motherboard handle it. 

[Kilrah]

25 minutes ago, Stellarisk said:

I was recommended to manually set the vcore over letting the motherboard handle it.

Well yes but that doesn't mean "set it to 1.2 and expect it to work", it means you adjust it small step by small step until you find the lowest stable setting, hopefully it's better than the default but it might not be.  

[Stellarisk]

9 minutes ago, Kilrah said:

Well yes but that doesn't mean "set it to 1.2 and expect it to work", it means you adjust it small step by small step until you find something the lowest stable setting, hopefully it's better than the default but it might not be.  

Ok so I started running it after resetting it to auto. The temperature goes up to 89 before dropping down into the 60s-70s. It doesn’t crash immediately but the temps seem high for thermal grizzly and a noctua nh-d15 while running small ftt 

[Stellarisk]

40 minutes ago, Bitter said:

Something is unstable, probably the CPU if it failed a small test. Set it all back to original settings and try again. Crashing out so fast usually happens when somethings volts are set too low, overclock too high, or maybe really unstable power delivery to the CPU.

So I switched voltages to auto rather than the 1.2. I then ran small ftt and it went up to 89 degrees before dropping down to the 60s/70s. Is this normal? It didnt crash this time but the temps seem a bit high for thermal grizzly and a noctua nh-d15.

[Kilrah]

If it works and doesn't throttle it works.

 

8700 has a pretty small die so thermal transfer gets limited by this in a way that at some point you don't gain anything by getting a better cooler. 

[Stellarisk]

39 minutes ago, Kilrah said:

If it works and doesn't throttle it works.

 

8700 has a pretty small die so thermal transfer gets limited by this in a way that at some point you don't gain anything by getting a better cooler. 

Sorry I’m newer to pc building. All I had done was transfer everything to a new case. What does that mean? I don’t know if it’ll help but Here is my vcore and here is The other voltage info   I think I understand that the temps simply can’t get better for that but could you explain a little more so I could understand what’s happening. I appreciate the help. Does this mean my CPU is going to die quicker?

[Bitter]

Use voltage offset instead of static core voltages if you want less overall heat and power use. Try lowering offset by 0.025 at a time until it's no longer stable then add back 0.010. Also take a look at LLC, that can be set too high by default and you can sometimes drop that lower to reduce that spike in heat when transitioning to high loads but possibly at the cost of stability.

 

The reason it spikes then falls is due to PL1 and PL2 limits kicking in. Prime95 is an absolute worst case scenario for thermal and power draw, it will never be that bad when gaming or doing almost anything else. If it's stable and doesn't throttle with Prime it'll be fine for everything else probably.

[Stellarisk]

53 minutes ago, Bitter said:

Use voltage offset instead of static core voltages if you want less overall heat and power use. Try lowering offset by 0.025 at a time until it's no longer stable then add back 0.010. Also take a look at LLC, that can be set too high by default and you can sometimes drop that lower to reduce that spike in heat when transitioning to high loads but possibly at the cost of stability.

 

The reason it spikes then falls is due to PL1 and PL2 limits kicking in. Prime95 is an absolute worst case scenario for thermal and power draw, it will never be that bad when gaming or doing almost anything else. If it's stable and doesn't throttle with Prime it'll be fine for everything else probably.

So I shouldn’t feel bad that prime hits 91 before lowering to 59-66?

[Bitter]

Depends on fan curves and case airflow.