990X and the 4.5GHz questions

[ShiroiKage]

Hello people,

I've been trying to get my i7 990X (other specs below) to 4.5GHz on all cores. I've hit a wall with my host clock frequency. The system is not stable enough to even boot as soon as I go over 165.

165, without Turbo, yields 4.3GHz which was stable overnight on Prime95. 166 host frequency causes blue screens and problems booting. 167 and above prevents even booting (Motherboard starts booting then goes to step 00 and freezes there. Sometimes restarts and tries booting again. The only way I could get things to run afterwards is thanks to the BIOS warning that the system could not boot and if I wanted to change settings or retry booting)

So, I decided to move on to Turbo overclocking to avoid changing host frequency. I increased both current and power limit overrides and increased the multipliers to 27 on all cores yielding a 4.46GHz max frequency, and I might be able to push it further. It has been stable for the last couple of hours under Prime95 and I tried a few minutes of Intel Burn-in test which went well-too.

Now, to my question. Is there an upper limit on how far the the host clock should be raised? I want to push the system further using that so as to get the RAM pushed even further. Also, is it a good idea, in general, to turbo-overclock a processor anyways?

PS: Temps are not an issue. The system is water-cooled and runs at mid to high 50sC under load.

Specs:-
Processor: Intel i7 990X extreme edition.
RAM: Corsair Vengeance 4 GB, 1600MHz (6 cards at 24GB total and running at default multipliers of 10)
Motherboard: Intel DX58SO2
GFX card: HD Radeon 6990 (955MHz GPU clock and 1470 Memory clock)
There's an ASUS 7.1 sound card.

 

[jamesriley94]

The base clock can cause issues when raised. To the extent that on the newer chips, even raising from 100 to 105 can cause issues.
Maybe you've just reached the limit. There isnt an upper limit so to speak - it's dependent on your chip as everyone's is different.
If it does work at 166, but works at 165 - I'd probably say that's your limit

 

[ShiroiKage]

I knew that host clock stressed everything when raised, but it's good to know that it's this sensitive.

Thanks.

 

[jamesriley94]

If you're going for memory OC - can you not decrease the base clock and up the ratio on the RAM?

 

[ShiroiKage]

I think I can, but I did not try to increase the mem multiplier yet. This is my first extreme processor and, from what I heard, the IOH is locked in Intel's processors and can only be increased using host clock.

Even before I began overclocking, I set the BIOS memory settings to the memory's factory defaults (1600MHz + voltages) and the BIOS kept under-clocking it to 1066.

 

[jamesriley94]

Tried doing it in XMP?

 

[ShiroiKage]

That's the profile I was talking about, the one the board ignored and went for the underclocked default.

The profile runs lower voltage than default, for some reason, and I have already exceeded its settings (I'm running a bit over 1600MHz, slightly above specs, and have the voltage raised a little as a precaution)

I will try using the profile's settings, mainly the multiplier, after I'm done stress-testing my processor for a couple of hours as it is running at 4.63 with turbo and I want to know it's stable before further messing with the memory.

 

[ShiroiKage]

Update: So there is this problem I might need help with.

Prime95 is returning a hardware fail error after about an hour of running. Did some digging and decided that I need to further increase the RAM's and Uncore's voltages. Also, I knocked down the Uncore multiplier to 18 from 20 as per the XPM profile.

It's running Prime95 again and was wondering if the changes I made were a good idea. Also, could the IOH stability be behind the hardware fail errors?

Thanks.

EDIT: Any ideas on where I should stop when pushing the Uncore voltage? Because I'm still getting hardware fail within the first hour of Prime95 ...

 

[jamesriley94]

Drop the RAM back to 1333mhz and run Prime again to rule out it being an issue with the CPU overclock.
That's the main reason not to use the BCLK. If you raise it, it can make either the CPU or RAM unstable, and you have no idea which is causing the problem.

Put the ratio of it down so it's low - leave the BCLK where it is

 

[ShiroiKage]

Well, I dropped BCLK before I read this message and it allowed for more stability (maybe because I was so close to the limit of that anyway)
I could run Prime for a couple of hours without problems, then I left overnight to come back to a crashed system. I reduced the multiplier and clock speed so the RAM is running within specs, apart from the Uncore.

I will try another couple of hours of Prime, do homework, leave it for the night then come back to it

Will report back then.
Thanks for sticking around, btw.

PS: Well this crash was something very odd. What happened is that I found my monitors on standby and the system frozen at 00. I reset the system a couple of times in and out of BIOS to make sure the changes to the RAM settings have been saved, and loaded the OS afterwards. The OS resumed everything as if nothing happened (Prime continued where is left, without error messages even, and so did everything) Could be the SSD? because this is the first time I've seen something like this.

 

[ShiroiKage]

OK, this is comical. I suspected that I'm stupid, but this confirms it.

So, that which I thought was a crash, turned out to be Windows going into standby. I formatted my device to move Windows to an SSD so that I can reboot faster when going in and out of BIOS (default power state = balanced ....)

I will run Prime anyways and see what happens.

Btw: What do you say to changing CPU voltage management to dynamic? The tool tip in the BIOS says that it's an automatic option with the reference set by the user. I like to set my minimum processor state to something around 90-95 and I don't want unnecessary voltage running though my chip.

 

[ShiroiKage]

Update: It seems that I got everything stabled. RAM was stable as soon as I went back to being in specs (1.5V and under 1600MHz clock. I'm at 1556 or something) and it took 2 hours of Prime no problem.

Processor is running at 4.5GHz under load nicely. What I want to try now is dynamic voltage with user reference. I tried, for a few minutes, to run Prime while monitoring voltage under dynamic with reference voltage of 1.382 or so (the one step below 1.4) and interesting stuff happened.
I set my system such that, at idle, the CPU is allowed to drop to 90% frequency (non-turbo) and that yields idle frequencies of 2.9 to 3.1GHz. Voltages at those frequencies are set to as low as 1.16V by the BIOS under dynamic. Under load, the voltage readings go up to 1.45 (stays static if the frequency is unchanging) and I want to know if 1.45V is too much, and if it is a good idea to allow frequencies and voltages to drop between idle and load.

 

[tinytomlogan]

It should do 200 BCLK no problem. Just make sure the ram is set to 1600 with a Multi of 20 to test it and then work from there.

I always turn off all the turbo eist speedstep rubbish and have a static clock too. That can cause instability in itself having the speed changing all over the place

 

[ShiroiKage]

Maybe that's what's going on here. I'm still getting my PC to crash when trying to run prime overnight.