Hi guys

just wondered if someone could offer an explanation why this happens

I have an oc i7 2700k running at 4.7 quite happily running fsx for hours with absolutely no problems,so I decided to see if I could get it up to 4.8 or 9 so I downloaded prime 95 real temp etc I then oc it to 4.9 ran the tests and it crashed almost straight away same thing happened at 4.8 so reset everything back to 4.7 and all runs fine again,However the strange thing is if I run prime 95 it runs for a couple of minutes then crashes the machine but in reality I can run fsx plus several other addons for hours with no bsod or any other problems I've checked the freq with aisuite and all cores show that they are running at 4.7 with no heat issues

so any idea why prime 95 and intel burn all fail with the burn tests

cheers

Quite simple, Prime and IB are much much harder on the CPU. They load your cpu to a full constant 100% non stop.

 

You can also see this when you monitor temps, they will be about 15 to 20 c lower when you run fsx compared to IB.

 

Basically you have an unstable over clock. 

 

Its up to you if you want to make it stable by increasing your voltage, but if you are happy with FSX performance, it really is your own choice. 

 

I would personally make sure your over clock is stable though. 

thanks for the info

I might have a look and tweak it and see what happens

is it the cpu pll voltage that needs tweaked? bit of a novice at this

thanks

You have to change the Vcore voltage, but if you don't know what you are doing exactly, I feel reluctant to tell you, because you can seriously damage your chip, or even destroy it.

 

I would really advice to read up on over clocking before you do anything else, because you need to know what you are doing. 

 

Here is a start: http://www.overclock.net/t/910467/the-ultimate-sandy-bridge-oc-guide-p67a-ud7-performance-review

However the strange thing is if I run prime 95 it runs for a couple of minutes then crashes the machine but in reality I can run fsx plus several other addons for hours with no bsod or any other problems I've checked the freq with aisuite and all cores show that they are running at 4.7 with no heat issues

 

so any idea why prime 95 and intel burn all fail with the burn tests

 

This is the dilemma, and the reason people like Asus frown upon synthetic stress tests.

 

What did you buy your CPU for, to run synthetic stress test all day? Or to run real world applications like FSX? I would guess the answer you will give me is the later.

 

I'm not saying you should ignore the fact that your CPU failed in Prime, but I am saying that the priority should always be how stable your system is when you run the software you use day to day.

 

To that end, pay attention to the fact that your overclock has failed pretty much straight away in Prime and take the necessary measures to correct the issue. However, running hours and hours of Prime like some people do, and the notoriously vicious IBT, is pointless.

Thanks outofphase

I had a read up before I started playing

I then used the aisuite rather than go into bios each time and I could monitor the temps and voltages a bit better.

I realised after I sent you the reply that it was the vcore that needed adjusted,anyway Ive had a fair amount of success with the stress testing and can now get a stable 4.8 and 4.9 but only for the stress testing I've throttled the vcore back slightly for normal running.

I can push the cpu voltage up to 1.385v which produces  a 1.568v vcore which is high and gives me a red warning but strangely if I run the stress test with those settings the vcore drops to 1.48 and no warnings with the oc at 4.9

the cpu temp gets a bit high but I need to give the radiator a clean which will no doubt help

I've changed my llc from normal to high also

In ai suite I have set various profiles that seem to work fine and I can get a stable fsx running at 4.9 with the cpu voltage at 1.380v which gives me a vcore of 1.495 most of the time goes up to 1.5 or down to 1.48

and I can get 25-30 fps around egll with max ai a/c and opus weather which has given me about 4-6 fps more now that I've gone from 4.7 to 4.9

will need to keep an eye on everything,but it all looks stable so far

so thanks

rgds

Your voltages are waaaayyyyyyy to high!

 

You have to remember that you are not only temperature limited. 

 

Once you go past a certain voltage, you are reducing the lifespan of your chip to, well, it depends, but it could be even weeks or hours.

 

Once again, I highly suggest you read up more before setting random voltages and using trial and error, because you can kill your cpu, and potentially your mobo with it.

 

From a quick search on the internet, I c you should not go past 1.425V on the 2700k, but I would advise taking a save margin and put your limit even lower.