Overclocking results in no sound

D

Deimos

[H]ard|Gawd
Joined
Aug 10, 2004
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I just upgraded my ageing system with a Xeon X5670, it overclocks like a champ, 200Mhz on the BCLK seems to run just fine (24 hours prime) for a final clock of 4.4Ghz HOWEVER my X-Fi Titanium is not happy, after running a game for a few minutes sound cuts out and is replaced by popping and ticking. FUUUUUUUU:mad:CK

I've been tinkering for a good number of hours now and the best I can come up with is setting the BCLK at 175, ram at 1:1 (1754Mhz ram speed which is pushing it really hard) for a final OC of 4.2Ghz but after setting the QPI/DRAM Core voltage to 1.3v the CPU gets super hot (98C).

Anyone got any tips for getting the BCLK stable at 200Mhz? at that speed I can run the ram at 1600Mhz (within spec) and the CPU is at least 20C cooler, otherwise I'll have to resort to a lower OC like 166 on the BCLK :(
 
Sounds like the PCI-E bus is running out of spec due to the OC causing your sound issues.
 
What I find really odd is that no other device has an issue, for example my board doesn't have native SATA 6GB/s, it has a Marvel controller that uses 6 PCIe lanes, no problem at all, video card is fine too, USB3.0 as well. Moving the sound card makes no difference, I even tried a different X-Fi Titanium (I have anothoer one in my HTPC).
 
Creative have always had issues with various things such as using IRG associated with other things, faster speed, more likely to have a problem with these things being "checked"

anyways, can you lock the pci speed at 100 like I can on my AMD board, apparently this can help to force things to not run faster then they should be running so they don't run out of spec, or possibly, if you have option of spread spectrum it could be beneficial of disabling this. http://www.techarp.com/showFreeBOG.aspx?lang=0&bogno=287

Thing is you are of course running things are a higher rate so things meant to "control" things such as EMI and so forth might be what's causing the issue cause it might be modulating it to much, and everything relies on specific clock signals, push it to much, and that's when shit happens :p
 
dragonstongue said:
Creative have always had issues with various things such as using IRG associated with other things, faster speed, more likely to have a problem with these things being "checked"

anyways, can you lock the pci speed at 100 like I can on my AMD board, apparently this can help to force things to not run faster then they should be running so they don't run out of spec, or possibly, if you have option of spread spectrum it could be beneficial of disabling this. http://www.techarp.com/showFreeBOG.aspx?lang=0&bogno=287

Thing is you are of course running things are a higher rate so things meant to "control" things such as EMI and so forth might be what's causing the issue cause it might be modulating it to much, and everything relies on specific clock signals, push it to much, and that's when shit happens :p
Click to expand...

I'm using X58 chipset, the PCIe clock is supposedly locked at 100Mhz regardless.

The whole thing is just plain wierd, I just can't figure out exactly WTF is causing it to happen. I just reset everything back, loaded the XMP profile, set the multi to 21, BCLK to 200, Ram to around 1600 (1604 or something), QPI to 3600Mhz (ish or around 7400GT/s) left all voltage at stock apart from Ram at 1.64v and CPU +.2v offset and it seems perfectly fine now. :confused:

As soon as I start messing around with any other voltage setting it goes FUBAR but if i drop the BCLK back down it works again.

Guess I'll just settle for 4.2Ghz provided it doesn't happen again...
 
Some of the hexcore xeons will run computationally stable at a higher BCLK than the buses (PLLs?) can operate stably at, the bus ECC may play some part in masking the issue. They will start to have unstable tsc due to missed cycles and tscs are synced between cores only once at boot, while most OSes assume "invariant tsc" means "totally synchronized tsc across all cores even in different sockets lol". The clock is unstable enough for audio distortion. I believe hissing is from jitter, popping and other strange artifacts (dithering between slowmo and realtime) from core-hopping between cores with tscs that once missed cycles and are now offset or are actively missing cycles and running slow.

If you switch your OS timesource to HPET by whatever means necessary it can almost entirely mask the issue, but under load HPET polling will consume upwards of 20-30% CPU on my system vs negligible CPU for tsc timesource. It's been suggested to me that there is a critical BCLK frequency threshold above which not just clock stability but performance is impacted, and that the two BCLK frequency thresholds may actually be the same. I suspect hiding the issue with HPET is probably shooting oneself in the foot, and I personally just backed off my BCLKs to about 186 where there ceased to be audio issues and enabled turbo.

For reference, I get ~4.1GHz all-core turbo and ~4.3GHz 2-core (x2 socket) turbo with a pair of x5650. With the x5670 you would get like ~4.7GHz at 2-core turbo with only 186 BCLK and ~4.5GHz all-core turbo. At that point you can probably back off most voltages a bit except VCore.
 
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I actually don't think it is strictly related to BCLK.

I'm running 4.2Ghz right now at the following settings:
CPU Ratio: 21
BCLK: 200
PCIE: 100
RAM: 1608
UCLK: 3216
QPI Link: 3600Mhz (one step above "slow mode")

CPU Voltage control: Offset
CPU Voltage: 0.20
(all other voltage at auto)

CPU Differential Amplitude: 1000mV
CPU Clock skew: Delay 300ps
IOH Clock Skew: Auto

And have yet to experience sound issues, however if I adjust any voltages upwards from here (apart from the last 3) sound issues start up again. I can't get to 4.4 without more CPU volts unfortunately.
 
I also noticed that if I use offset voltage control the CPU won't necessarily pull all the volts available to it, so even if I set it to 0.20v the CPU won't actually go that far, if I start raising the clock it pulls more volts without me actually changing it at all which I find interesting.

For example, I currently have it set as above and the max volts I'll see is 1.24 but if I set as follows:

CPU Ratio: 24
BCLK: 175
PCIE: 100
RAM: 1758
UCLK: 3516

Without adjusting the voltage at all I see 1.4v on the core. :eek:
 
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#1. CPU voltage offset is not going to get you where you want to go. Use manual voltage.

#2. Set all other voltages to manual as well. Using Auto on any of them is most likely going to drive them way above what you need or want.

#3. You may need IOH skew as well. I used to do 300ps.
 
OK thanks.

Still tinkering away, I just realised that I didn't do a full CMOS reset when I changed the CPU so that has been done now.
 
FINALLY got to the bottom of the issue.

It was my f*cking power supply, the 3.3V was only supplying 2.98V which apparently is fine for running a CPU overclocked to hell but the soundcard won't have a bar of it unless the whole system is stock.

Its a Silverstone ST1000-P, I have another one in my server so I just swapped it out, the replacement is still less than 3.3V though, 3.15V but that is enough to resolve my issue.

Seriously WTF, I'm going out to buy a SeaSonic ASAP to replace this POS. :mad:
 
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