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Skylake Fclk and direct relationship to PCIE Bus

 
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post #1 of 2 (permalink) Old 07-23-2018, 01:02 AM - Thread Starter
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Question Skylake Fclk and direct relationship to PCIE Bus

Hi Everybody !!

So i've been trying to find some solid info on Fclk and i can't really find much more than people had "issues" that weren't really discussed above 1400mhz

I Decided to start messing around with my Bclock. I bumped it up to 150 and adjusted CPU, Ram, Cache to suit. The pc ran awesome, It was like it had these weird little hiccups before (probably superficial) that had dissapeared. I Noticed that my Fclk(system agent) had jumped up to 1500mhz as i hadn't adjusted it in bios. It stressed fine P95 blend for an hour and then i proceded to run a stream... After about 7 hours of solid Escape from Tarkov which were talking 100% load on my Vega 64 and around 40 - 60 % load on my 6700K the video card decided it was going to suddenly throttle down to windows spec speeds, IE 300mhz GPU - 30-50Watts power draw.

I was wondering how does Fclk correlate to the PCIE Bus ? I know with early PCIEX1 when it was strapped via the Northbridge you could adjust the Mhz slightly for more stability on multi gpu setups ie 100-113Mhz.. I was wondering how having an fclk of 1500mhz directly relates to the gfx card. And if anyone has much experience with running it overclocked and hazards or issues that would present themselves as an indicator that something is wrong ?

Escape from Tarkov is an unoptimised rescource hog of game so its possible the card meltdown was due to having a low setpoint of HBM. But i can't help but wonder if it was related to that overclock i was running with the Fclk at 1500mhz. I have included a pic of my current run, i have opted for a X8 fclk and a 170bclk. The pc feels better than it did running at 4.8 @ 100bclk
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post #2 of 2 (permalink) Old 08-01-2018, 08:33 AM
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FCLK is responsible for connecting the PCI-E controller to the rest of the system agent/ring bus.

https://www.anandtech.com/show/9607/...-optimizations

Most parts will not be stable at 1.5GHz FCLK and you cannot stress/test FCLK with CPU/memory tests like Prime95 as they will never touch PCI-E. Errors on PCI-E from an excessive FCLK could easily cause GPU related issues.

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6700k , fclk , Overclock , system agent , vega 64

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