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A bit of advice needed for AMD FX FSB overclock

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Jan 1, 2021
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System Name Enter name here
Processor Ryzen 7 3700x w/ PBO
Motherboard Asus Prime B550 Plus
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Memory 2x16 Crucial Ballistix 3200 Micron E-die@3800Mhz 1,41 18-16-20-18-38-58
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Benchmark Scores CInebench R20: 5085
Hi everyone and happy new year ! :lovetpu:
I admit it, i've been a long time lurker here since 2016, thanks to Der8auer and Buildzoid mostly.

I seek today your advices for overclocking further my old fx 8350.
Heres my system specs:
CPU:Fx 8350 (with Noctua NT-H1 paste)
MB: MSI 990FXA GD-80 (8+2 true phases)
RAM: Kingston DDR3 4x4Go 1600Mhz 1,65v @1,506 Mhz (1T 9 10 10 27)
Cooling: Hyper 212 with two HighRPM Silverstone FM122 fans on push & pull
PSU: Cheap 550w bronze (OEM from HEC)
VGA : Asus strix 980 (-72mv ,88% Powerlimit, stock clocks)

And heres my CPU clocks and voltages entered in my BIOS:

CPU Clock: 4407MHz-4633MHz
Multiplier: x19,5-20,5
FSB (equivalent to Bclk on intel): 226
CPU-NB clock (northbridge): 2486 Mhz
CPU Vcore 1.42v
CPU-NB : 1,36v (this helps when increasing FSB)
NB voltage: 1,27v
APM : off (I paid for all the phases, i want them all! :rockout:)
C6 & C1e States: off
HPC mode: on
HT-link: 2712MHz

As you might know this motherboard doesn't have any LLC presets so i get a 0.04v Vdroop on vcore on loads.
I have Cool&Quiet and turbo enabled because i want dynamic clocks (it gets hot during summer).
Through some software, I make them not go below 2,3Ghz though.
I have tried setting software P-states but the voltages gets very wonky and i'm not sure about that.
Temperature wise i get stable 53°c under prime95 (@60% fixed fan speed)

In most games i play, i get cpu bound so i want to OC a bit further and i know for fact that increasing the FSB (and northbridge) helps a lot in singlethreaded performance.
Also don't say "upgrade already!" because if i could, i would lol. (plus FX overclock is fun)
So i'd like to push FSB to 240 or more if i can, i have not tried 231+ yet.

If you guys happen to overclock fx, help would be very much appreciated :D

Edit: My cinebench r15 scores are around 725cb at the moment (stock was 642cb).

I forgot to mention when i say dynamic clock, all the cores runs at turbo (x20,5) speed under load with no throttle. (without any vcore bump from x19,5 though)
So just assume i run x20,5 multiplier.
And I do run this system daily.

Thanks.
 
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I really suggest you don't use base clock overclocking, that's going to introduce so much more instability for little gain.
 
I really suggest you don't use base clock overclocking, that's going to introduce so much more instability for little gain.
AMD's of this socket and older like FSB/BCLK to be part of OC'ing it, running it at 226FSB is OK.

The only way instability comes in is if you don't tweak to accomidate the increased FSB.

I've noted with mine they only like a certain amount of multiplier or lower used, if running better methods of cooling they tolerate it better but for the most part water kinda restricts it to about 21or 22x max multiplier as a norm I've ever seen without issues.

AMD's up until this socket (AM3+) came out always want a mix of multiplier and FSB used, that's where they do best instead of all multiplier like later Intels like but even with those, anything from Socket 775 and older like a mix of multi and FSB too. ;)

Tips:
Keep your CPU-NB speeds around 2400, Vishera's do not like it much higher and can get fussy when you try it, plus there are no gains worth the effort to crank it past 2400 anyway.
Zambezi can go higher but you've got a Vishy so that's what you'd need to base it on.

Keep CPU voltage itself below 1.5v's, esp if on air or else. With water you can cheat but only by a little if that much, based on the exact chip in use.
Watch VRM temps, any problems wiht your VRM's will make it crash-prone and load temps around 62c or higher usually means it's crash-time for it.
 
Thanks for your replies, :love:
I have a fan controller on a 5,25" bay that control manually fans (Scythe kaze server) with some thermal sensors i can hook up to. (vrm, northbridge)
My temps on load are fine during winter, having air cooling provides airflow on the motherboard so that's nice.
I also have lapped the copper base on my hyper 212.
8370 might be better binned than 8350 too.
So i will dial down NB and HT-link multipliers to see if i can push fsb a bit.
criss2984 when you say noise, are you thinking coil whine or noise due to fan speed ?
 
8370 is supposed to be a better bin but in reality most, if not all FX chips clock about the same.
It's what voltage you need to get a certain speed is the difference between chips and it's just the silicon lotto in play with all that.

8370's probrably need a touch less voltage based on it's bin.
Also make it a point to test and see how little voltage you'd need for the speed you want with stability, the less voltage used the better for keeping temps under control under load, not idle and always base your temps on load temps. What's seen at idle is meaningless for the most part aside from wacky-high temp readings at idle which indicated a mounting problem wih the cooler, improper TIM application, cooler issues in general and so on.

Keep CPU-NB voltages around 1.20v's and speeds around 2400 as said, also realize anytime you raise the FSB the other speeds will also increase so wacth that in the BIOS when setting speeds vs the actual FSB used. Don't forget to keep an eye on RAM speeds too, those will do like the rest as FSB speed is increased and don't be suprised if you must use a RAM divider to keep RAM speeds within tolerance. If using the 1333 divider for example that will give you about 1666 RAM speed @250 FSB.

Be sure to take all these things into account anytime you start raising FSB and you'll be fine.
 
My old 8370 could do 4.5~4.6GHz with 1.38~1.4V. I think all 8300 series can do about the same speeds but with different voltage maybe.
Keep in mind that on those speeds/voltages the CPU power draw is 200+W. The amount of heat is enormous and I was "forced" to turn into AIO for cooling.

I was always tried to keep a balance between FSB and multies. Around 215~225MHz for FSB. CPU around 4500MHz, HTLink/CPUNB around 2600/2400MHz and DRAM 1800~1900MHz (rated 2133MHz)
 
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I just re-applied thermal paste on the cpu, i tried to put thermal sensors but those don't seem to work.
CPU temps dropped by 3°c. (50c max on loads)
Also CPU-NB (or NB) voltage was way too high (i got corrupted windows files, I had to recover and reset Bios)
Currently i have 1,29v on CPU-NB, 220FSB and x20,5 multiplier (4,5Ghz).
The thing is, I've seen some people running this cpu @4,8ghz with about 780cb score on cinebench R15, with my current settings i barely do 700cb.
This motherboard doesn't have vCore slider over 1,45v (max value is 1,448v) anyways so i won't get much more.
 
Looks like you're at your voltage limit. Now it's just fine tuning what you can and going from there.
 
I just re-applied thermal paste on the cpu, i tried to put thermal sensors but those don't seem to work.
CPU temps dropped by 3°c. (50c max on loads)
Also CPU-NB (or NB) voltage was way too high (i got corrupted windows files, I had to recover and reset Bios)
Currently i have 1,29v on CPU-NB, 220FSB and x20,5 multiplier (4,5Ghz).
The thing is, I've seen some people running this cpu @4,8ghz with about 780cb score on cinebench R15, with my current settings i barely do 700cb.
This motherboard doesn't have vCore slider over 1,45v (max value is 1,448v) anyways so i won't get much more.
I'm really curious to see a screenshot like the one below with this CPU. I didnt use HWiNFO back then...

1609879170549.png
 
Sure, but vcore is quite a bit different from HWMonitor.
The socket temp is the one display on the Postcode of the motherboard which is TMPIN0 on HWM or Fintek F71889A: CPU.
I believe HWmon Vcore is the accurate one. Obviously power sensors aren't accurate at all.
There's also a picture from inside the case, when i re-applied thermal paste and tried to put sensors. (loads of dust yes!)
I had to solder the fans for some reason too.

EDIT: +5v and +12v on HWmonitor are bugged as well.
 

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On HWiNFO the VID is not what the CPU is getting. VID is just a request form CPU (Voltage I Demand some may say). There must/could be another sensor for the actual voltage.
Anyway I was expecting the whole picture, and from the latest version (v6.40) not a 6.5 years old one...

 
Sorry, I didn't mean to be rude..
There you go
 

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Sorry, I didn't mean to be rude..
There you go
You weren't... Why would you think that?

Thanks for the pic!

The CPU voltage is the "Vcore" you see on one of the Fintek sensors.
Nice HT/NB speeds. What RAM you have? Cant increase speed?

Your PSU is indeed a cheap one as you mention. Every rail (+3.3V, +5V, +12V) is below the rated voltage. You should consider getting a better one.

I wonder if the reported "CPU Power" is real and what is, on full CPU load...

EDIT:
The 12V is far too off from the spec... If its real. It shouldn't be below 11.4V
 
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Well that's me being oversensitive, don't worry about it:toast:
Thanks for pointing that out, my PSU was making a slight coil whine since last week-end.
I guess i was already pushing it at its limit.

The +12v rail drops at 11,1v on loads lmao.
I'm freaking out every time i turn on my pc now.
Bios resetted, i will wait to buy a new psu before any other attempts.
This time 650w or more.
 
Yeah, its wonder you dont crash every time that goes below 11.5V under load.
Its not all about Watts. Efficiency and quality also. Quality the most.
PSU selection is no easy and simple task. The one component of the system that needs to be as stable and reliable as it can be, whithin reason.
A 650~750W will be ok for your system, depending also on the GPU you have. For sure its better to be 80+Gold, but not all Gold rated are created equal. The tolerated limit (within specs) of voltages is supposed to +/-5%.
+12V: 11.4~12.6
+5V: 4.75~5.25
+3.3V: 3.135~3.465
A quality PSU is never off more than 1~2% at most under heavy load.
I suggest to research and read actual reviews of PSU units. As for brands look for Seasonic, EVGA, Corsair, BeQuite. All of them have quality units, but also a few bad models.

Anything from Tier A/B will be fine
 
Well that's me being oversensitive, don't worry about it:toast:
Thanks for pointing that out, my PSU was making a slight coil whine since last week-end.
I guess i was already pushing it at its limit.

The +12v rail drops at 11,1v on loads lmao.
I'm freaking out every time i turn on my pc now.
Bios resetted, i will wait to buy a new psu before any other attempts.
This time 650w or more.
Yes, that PSU it clearly not working correctly and is in need of replacement.
Just don't cheap out on one, get a good, known make and model to help ensure no issues with it. May cost more but still cheaper than killing it and then having to replace everything - Including the PSU itself (Again).
 
Thanks all for your help, i could avoid some nasty bugs before it was too late.
I bought a Coolermaster MWE v2 bronze 650 (B tier) that should arrive by monday. (@58€ only :D)
There's should be some room to overclock my gpu as well (not a whole lot though).
I'll keep you updated once i receive it.
:love:
 
If I remember right mine was stable at 233mhz fsb with a 990fx mobo, and try to keep the nb clock under 3ghz if you don't have a fan blowing into your case.
 
Hey, I'm back!
My new PSU is on and running, i stressed cpu only with one cinebench r15 run and 10min prime95 small FFTs (I ran HWinfo during these).
I think the voltage sensor on my motherboard isn't that accurate because i supposedly gets 11,6v dips but its still rock stable so idk.
It isn't as bad as the old one which went down to 11,028v during the same loads..

The good point is CPU holding 4,6ghz at 1,355v which is nice.
I'll tweak a bit to see if i can get further.
 

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Hello again.
I thought i'd give you guys an update because i made some major breakthrough. :D
For some reason to access the higher (above 1,45v) vcore values on this board, you have to clear cmos then enter bios right away.

It would be weird for msi to cap voltages on its top tier motherboard, right ? Sooo i'm glad i found this.
The temps though... o_O
With 1,51 vcore in bios (vdroops to 1,44v on heavy loads) the cpu goes up to 75°c. (not socket temp, the real one)
This temperature sensor becomes accurate above 45°c.
I let the fsb sit at 225Mhz which i find quite stable, but i pushed to 21,5x multiplier. (4,8Ghz)

The blue covers on the heatsinks of the MB were removed just in case too.
I doubt i would go any further voltage-wise with my current cooler.
If you guys happen to own an 990fx msi board feel free to pm me if you need help.
Thank you all :love:
 
With 1,51 vcore in bios (vdroops to 1,44v on heavy loads) the cpu goes up to 75°c.
No thermal throttling at 75C? Personally, I wouldn't feel comfortable running an FX at that voltage and temperature 24/7. Also, you'd see higher gains using faster memory - rather than going for the maximum CPU clock.
 
No throttling but if i put any less vcore, prime95 gives me illegal summout errors.
Since the firsts posts i also disabled turbo.
I can't manage to OC my ram reliably with 4 sticks. I have kingston hyperX Genesis 1600 @1,67v (stock is 1,65v), even with 2T 10-11-10-30 its not stable above 1700Mhz.
Prime95 is the worst case scenario, i doubt any game would come close to this load and temperatures.

EDIT: Forget what i just said I managed 1812Mhz with those settings, CPU-NB just needed more voltage.
I also downloaded the lastest version of P95 that doesn't heat as much. The CPU weirdly, is peaking at a cool 62°c.
I don't really know what to think at this point..
 
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No throttling but if i put any less vcore, prime95 gives me illegal summout errors.
Since the firsts posts i also disabled turbo.
I can't manage to OC my ram reliably with 4 sticks. I have kingston hyperX Genesis 1600 @1,67v (stock is 1,65v), even with 2T 10-11-10-30 its not stable above 1700Mhz.
Prime95 is the worst case scenario, i doubt any game would come close to this load and temperatures.

EDIT: Forget what i just said I managed 1812Mhz with those settings, CPU-NB just needed more voltage.
I also downloaded the lastest version of P95 that doesn't heat as much. The CPU weirdly, is peaking at a cool 62°c.
I don't really know what to think at this point..
Good job on the memory overclock! What specific Prime test are you using? What are your ambient temperatures?
 
Thanks!
The old one was version 29.4 build 8 (from 2018) while the new is the latest 30.3 build 6. I ran all tests presets on both for about 15min each.
My ambients are about 15 to 17°c, I like it cool.
The CPU-NB is related to the memory controller which makes sense i beIieve.
I used aida64 to make a comparison, the one with the cpu at 4,73 wasn't stable on p95.
However the other one is rock stable.
 

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OK, here's mine for comparison. You can see that higher CPU clocks do not immediately translate to better performance:

fx8300.jpg


Your 15 C ambient is incredibly low. Are you gonna keep your room temperature at that level for the whole year? ;)
Also, 15 minutes in Prime is no sign of stability, under any of the presets. For a more accurate approach try running Prime small FFTs for at least an hour, then large FFTs for the same amount of time. And watch your VRM temps.
And could you tell me how you monitor your CPU for thermal throttling?
 
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