• Competitor rules

    Please remember that any mention of competitors, hinting at competitors or offering to provide details of competitors will result in an account suspension. The full rules can be found under the 'Terms and Rules' link in the bottom right corner of your screen. Just don't mention competitors in any way, shape or form and you'll be OK.

FCLK overclocking

Soldato
Joined
18 May 2010
Posts
21,568
Location
London
This bothers me and I have not managed to get a straight answer.

When you find out what your max FCLK is, do you change any voltages or do you just up the FCLK frequency and then apply the ram speed and see how it goes?

My 3700x for example if I set the FCLK to 1900MHz leaving ram at 2133MHz (basically untouched) the PC will happily operate like this.

I only see problems when I add the ram at 3800MHz to the equation.

I get audio corruption etc...

So do I have to apply any voltages to get the FCLK to work with my ram at 3800MHz or is it just a case that this wont work for me.

Last time I played with it I believe it took around 1.2v SOC to get rid of the audio corruption.

But 1.2v is too high for PCIe 4 devices from what I understand.
 
Associate
Joined
10 Aug 2009
Posts
690
Location
Malvern
I thought the sweet spot for ryzen 3000 was 1:1 3600mhz, that's what I run at, no adjustments necessary, soc set manually at 1.1
 
Soldato
Joined
30 Mar 2016
Posts
2,850
Location
East Lothian
I have my 5800x set at 3866 and FCLK at 1933 but left the voltages at auto. My RAM was purchased with a provided DCOP / XMP profile of 4000 Mhz at 18-22-22-42. Aside from the notion that Ryzen 5000 series are supposedly happier at a higher FLCK I image the principal remains the same. If your CPU can handle the fabric clock at 1900 (no guarantee from my understanding) then the target would be to have your RAM running at 3800 so that it's coupled (1:1). When you're uncoupled such as having the MCLK set at 2133 and the FCLK at 1900 then your memory controller or uncore frequency (UCLK) will be running at half the speed of your MCLK as I understand it, so this may be why the PC is happily operating like that as you say. Once you couple the M and F clocks at the same frequency, then the UCLK automatically matches this frequency. It would appear that your set up isn't stable with all three clocks running at that high a frequency. I personally don't know if manually tweaking voltages will be able to overcome that or not though.
 
Last edited:
Soldato
OP
Joined
18 May 2010
Posts
21,568
Location
London
Yea at the moment I have 3600MHz at CL14 speeds so it's as good as 3600MHz can get.

I was just wondering if some of you running 1900 on the FCLK where actually applying n voltages to get there or if you just set it along with the ram speed with out any tweaks.

It sounds like if it will work it will work without any tweaks to voltages etc.
 
Soldato
Joined
30 Mar 2016
Posts
2,850
Location
East Lothian
Yea at the moment I have 3600MHz at CL14 speeds so it's as good as 3600MHz can get.

I was just wondering if some of you running 1900 on the FCLK where actually applying n voltages to get there or if you just set it along with the ram speed with out any tweaks.

It sounds like if it will work it will work without any tweaks to voltages etc.
Yeah I think so too.
 
Soldato
Joined
15 Oct 2019
Posts
8,685
Location
Uk
Yea at the moment I have 3600MHz at CL14 speeds so it's as good as 3600MHz can get.

I was just wondering if some of you running 1900 on the FCLK where actually applying n voltages to get there or if you just set it along with the ram speed with out any tweaks.

It sounds like if it will work it will work without any tweaks to voltages etc.
I had to tweak VDDG IOD up from the board default of 0.950 to 1V to eliminate WHEA errors.

I also dropped SOC down from 1.1 to 1.05 as it didn't effect stability and less is always better.
 
Associate
Joined
10 Jul 2013
Posts
16
Location
UK
I had to tweak VDDG IOD up from the board default of 0.950 to 1V to eliminate WHEA errors.

I also dropped SOC down from 1.1 to 1.05 as it didn't effect stability and less is always better.

Thank you Joxeon. My RAM's running at 3600 CL14, FCLK at 1800 but I'm looking to ramp it up to 3800 / 1900 for an AMD 5900X.

I've seen 'WHEA' errors mentioned a lot but how do I check for those please?

I have Aida64 if that can be used? Sorry, it's been a very long time since I overclocked an AMD FX8150 and I'm way out of the loop. It seems a lot more complicated than it used to be! Any advice would be appreciated.

Thank you
 
Last edited:
Soldato
Joined
15 Oct 2019
Posts
8,685
Location
Uk
Thank you Jason. My RAM's running at 3600 CL14, FCLK at 1800 but I'm looking to ramp it up to 3800 / 1900 for an AMD 5900X.

I've seen 'WHEA' errors mentioned a lot but how do I check for those please?

I have Aida64 if that can be used? Sorry, it's been a very long time since I overclocked an AMD FX8150 and I'm way out of the loop. It seems a lot more complicated than it used to be! Any advice would be appreciated.

Thank you
They should show in event viewer.

The first thing I'd do if you haven't already is update to the latest bios before you start playing with ram as fclk stability has improved quite a bit from the earlier bios and the chances are you should just need able to set speed and timings and the board will set the correct SOC/VDDG voltages although you will probably still need to set Vdimm voltage which may need altering a bit depending on how tight you try to run CL, 1.4~1.5 will be in the ballpark of what you need.

If you download the dram calculator it comes with a free memtest utility so once your done tinkering you can leave it running overnight to make sure of no errors etc.
 
Associate
Joined
10 Jul 2013
Posts
16
Location
UK
Thanks a lot for the fast replies.

Yes, it has the latest BIOS, thank you Joxeon. The DOCP was listed at 1.45v but I had to increase it to 1.475v as the PC wouldn't start.

I tried increasing the frequency by 200mhz, voltage to over 1.48 (sorry, I didn't note down the number) and it worked with a cold boot. But when I put the FCLK to 1900 it didn't work a few days ago so I reverted the adjustments. Nearly everything is set as auto again, except RAM voltage at the moment.

I'll try the DRAM calc and see if that sheds some light for 200mhz RAM oc vs timings then will try FCLK again, thank you.
 
Soldato
Joined
11 Jan 2019
Posts
3,214
Location
bedlam
Keep all setting at stock.. at spd speeds set ram at 1.45v and 3800mhz and test.. if its stable push Fclk to 1900 and retest.

Don't use xmp use the loose spd timings.
But test the ram at 3800mhz with fclk at stock.

The extra 200mhz on ram and 100mhz on fclk will give little to no performance gain. Sticking at 3600/1800 and working on timing would give more gains
 
Associate
Joined
28 Oct 2009
Posts
2,102
Location
Dark Side of the Moon
This is how I test FCLK.

1) Set the following volts.

SOC 1.25
IOD 1.2
CCD .95
RAM 1.4 ( I have bdie)

Slowly up your IF clock till you reach the speed you want, for 3000 stop at 1900, for 5000 keep going till you fail to post.

Once max IF is met, reduce SOC and IOD together in 25mv increments untill you fail to post. Then +25mv.

Now bring the ram up to the correct speed, set very lose timings. You may need to increase SOC and IOD to bring stability, they should stay with 50mv of each other as per my readings but my chip likes that to be 30mv.

Once the RAM is at the speed you want now work on timings and from my experience, ram v will bring stability here.
 
Associate
Joined
10 Jul 2013
Posts
16
Location
UK
Thanks again for the replies.

I downloaded the DRAM calc and it turns out, there was another BIOS update a few days ago so I downloaded that. I tried leaving everything at auto and getting 3800mhz but then the PC wouldn't start and had the yellow RAM warning light on the Mobo.

After eventually resetting CMOS and using DOCP again, I've had to increase the voltage for DOCP (3600mhz CL14) to 1.48 now.

Seeing as the difference would be so insignificant and as I know I'm beat, I think it's time to call it quits.

Thanks for the help again though. All the best
 
Soldato
OP
Joined
18 May 2010
Posts
21,568
Location
London
This is how I test FCLK.

1) Set the following volts.

SOC 1.25
IOD 1.2
CCD .95
RAM 1.4 ( I have bdie)

Slowly up your IF clock till you reach the speed you want, for 3000 stop at 1900, for 5000 keep going till you fail to post.

Once max IF is met, reduce SOC and IOD together in 25mv increments untill you fail to post. Then +25mv.

Now bring the ram up to the correct speed, set very lose timings. You may need to increase SOC and IOD to bring stability, they should stay with 50mv of each other as per my readings but my chip likes that to be 30mv.

Once the RAM is at the speed you want now work on timings and from my experience, ram v will bring stability here.

SOC 1.25v? Isnt that a bit high? Unless this is 5000 series specific?

I thought anything over 1.2v was bad for PCIe4 devices?
 
Associate
Joined
23 Apr 2009
Posts
2
A starting point to find your max FLCK, then lower. For me, my 3900 and 5800 ended around the 1.1 mark.
Well I am glad to hear someone with a 5800x could hit 1900, I hit a hard ceiling at 1866 with my ram at 3733. I've tried using higher SOC voltages but it wont post. If I decuple my ram I can OC it up to 3833 CAS 16. I tried FCLK 1933 for grins and it actually posts but Windows wasnt stable and the Bios was slow letting me know something wasnt stable so I just reset it and went back to previous max. The recent BIOS versions allowed me to hit these clocks, maybe a future one will let me go just a little higher.

Honestly a 133mhz memory OC isn't bad but I would love to hit the full capability of the Ram. I almost bought 3800 CL16 ram but glad I went with the 3600 now. I may get some 3800 CL14 if the prices ever come down. Plan to get a 5900x down the road or an XT they a rumoring about.
 
Top Bottom