Ryzen 5000 Series Overclocking Options

[NoddyPirate]

Many of you will have seen some of my threads and posts recently regarding my escapades with Overclocking my Ryzen 5 5600X. In the past day or two while investigating some undervolting issues I was having, everything I have played with to date suddenly seemed to become clear and simple in my head. So I thought it would be useful to try to compose a sort of 'Overclocking for Dummies' explanation of the various settings I have used.

This is not, and would never claim to be, definitive, or necessarily accurate either, and should be seen as nothing more than just my attempt to simplify the concepts and give a head start to anyone else looking into it for the first time. Treat it as generic and non-specific, even where I cite my own values and figures.

As always, Overclocking is to be done at your own risk (and peril ) and is outside the basic terms of your PCS warranty - in that if you damage something from doing this then it's your problem - but with care I believe it can be done entirely safely. Set yourself limits on voltages and power draws and don't exceed them. Understand the limitations of not just your CPU, but also your Motherboard, VRM, PSU and Cooling Solution.

Right so, enough of all that - let's get into it......

 

[NoddyPirate]

MANUAL OVERCLOCKING

To begin, let’s briefly consider the Stock situation. Here are my numbers with my 5600X. One the left vertical axis is voltage (average Core VID here, but it doesn’t matter for the explanation), and on the right vertical axis is frequency. Along the bottom is CPU Load. NOTE – I don’t mean just core or thread load here, I mean combined processor and power loading.

On the upper left ‘plateau’ you can see my Stock Single Core or more correctly ‘Low Load’ limit of 4.650 GHz at 1.330 V – this is where my best cores do their thing. As the CPU Load increases the maximum allowed frequency reduces to keep my weaker cores more comfortable, until I reach 100% Load at 4.250 GHz and 1.165 V (This is quite low for stock – but better cooling than mine will give you better results here). You can also see that the higher the frequency, the higher the voltage required.

With a Manual Overclock, we erase all that behaviour and set a single value for both frequency and voltage. On a Ryzen 5 5600X you might conceivably manage something like this:

This isn’t as great as it looks - because the voltage is both high AND constant whenever an above idle CPU load exists. At high load that high voltage also means VERY high power draw and high temperatures.

The 5600X is a bit unique however, other 5000 series CPU's are unlikely to be able to Manually Overclock like this to reach or exceed their stock single core boost frequency, because all the cores just can’t be pushed that far together. So their chart might look like this – with a section of unused and unavailable performance out of reach.

For gaming and lighter workloads this is simply and plainly worse that leaving everything Stock. For production workloads there is a benefit if you can handle the heat!

In my view there is a better way to compromise and keep all workloads happy……

 

[NoddyPirate]

PRECISION BOOST OVERDRIVE

With PBO we can firstly override stock power limits to give the CPU the opportunity to push harder. You can allow the Motherboard decide what's best (basically take this to mean no limit at all – the CPU will pull as much power as it can get – be careful with this!) – or set your own values. Let’s bring back the Stock chart and add in what happens with my chip when I increase the power limit from 76W to 90W.

You can see that the low load side of the chart is unaffected because it is frequency limited, but the high load side has been allowed to use higher power (and higher voltages) to attain higher frequencies. The CPU temperature obviously goes up now too at the new higher power. So far so good though. However, we can refine this further by using the next bit of cleverness…..

 

[NoddyPirate]

PRECISION BOOST OVERRIDE

Not to be confused with the similarly named Precision Boost Overdrive above, this allows us to increase the maximum Global frequency limit – giving higher low load boosts and pushing the left side of the chart up for us. Here’s what it looks like with a 100 MHz Override added to our previous step:

The great thing about this, is that this new upper limit happens under low load and only stresses the best cores. As the load increases the frequency drops off – all just like the stock situation – only better! The only issue here is that the voltage under these low load boosts is getting a little uncomfortable.

Now, it must be said that high voltage is not in itself a dangerous thing when the overall power draw, and temperature, is low. And as we would only see these highest boosts at lower loads, the risk is somewhat reduced, but we can still do better……

 

[NoddyPirate]

CURVE OPTIMISER

This allows to force a negative offset to the power profile voltage curve. Effectively, it is undervolting the CPU. Undervolting brings no damage risk with it, but can cause some instability as we will see later.

To better explain why this Curve Optimiser is so fantastic, lets consider what it does. On the left here you will see a totally arbitrary and made up example of a voltage curve. As the core frequency increases, the voltage must increase too.

On the right is a red line showing that original curve but now offset. You can see that if we maintain the same frequency we can now achieve it at a lower voltage. Or if we keep the same voltage we achieve a higher frequency:

It’s this latter feature – sneaking more frequency out of the equation – that we can use to our advantage. Let’s go back to our Stock situation, add the Negative Offet and see where we get. I have added a full 30 unit offset in this example – equating to about 150 mV depending on conditions (NOTE - the 5800X, 5900X and 5950X will only remain stable at increasingly lesser Offsets than this, with the 5950X accepting perhaps only 5 units or so.)

On the left side of the chart we are frequency limited – so we still get the same boost – but now at a much lower voltage . On the right side of the chart we are not frequency limited, so we get more frequency. And because the power hasn’t changed we get that extra frequency at the same CPU temperature. Great!

Let’s put our Precision Boost Overdrive back in now:

Our high load frequnecies have now been lifted even further with the extra power available. The chart on the right has gotten a bit funky because the voltage under high load is now actually higher than under low load. But we are still way below stock single core voltages in either case.

Finally we can add in our Precision Boost Override again:

This is looking great now. Lots of high frequnecies all over the place and really low voltages everywhere too.

We could possibly push things further but that brings us to the final saga....

 

[NoddyPirate]

INSTABILITY with CURVE OPTIMISER

I suffered some crashes when I pushed my negative curve undervolt further and further. My assumption was that my system was becoming unstable due to inadequate voltage at full idle. However, this turns out to not be the case. To explain what you might see, here are our final two charts. I’ve removed all values from these to make them as simple as possible – as the numbers are actually quite complicated when you try to include them!!

I have added a red line at the top indicating the point at which things become unstable. You can see here that if I push my Override any further then I will hit this line under low load boosts. The only way I can give myself more room is by reducing the undervolt first to push that line higher up. Doing so however will create quite elevated voltages (because the boost will be higher AND the undervolt will now also be less at the same time)

What happened with me is I just slightly crossed that red line without knowing it. So my situation looked like this:

Every now and then a core would be asked to boost too high at too low a voltage and the system would crash. I solved my problem by reducing my undervolt, but hopefully you can see that I actually have another option here? If I just reduce my Override (not my Overdrive - it's easy to confuse them!), and get the yellow area back under the red line, I can keep my undervolt. In fact, I was able to increase my undervolt to the maximum amount, by reducing my Override to suit – and have remained stable without crashes ever since.

For me this works fine, because my workloads prefer better all core frequencies over single core - and reducing my undervolt would actually hurt my all core performance. I don’t mind giving up a little of that extra single core boost to retain or even increase that all core performance, but you can balance the two as required yourself.

That’s it!

 

[NoddyPirate]

APPLYING A CURVE OPTIMISER OFFSET WITHOUT APPLYING A MANUAL PBO

As explained above this is nice because you can get a performance boost while your thermals remain the same or better.

On my BIOS layout there are two locations where the Precision Boost Overdrive (or PBO) settings can be changed; on the ‘AI Tweaker’ page and within ‘Advanced’ – ‘AMD Overclocking’, but only the latter gives access to the Curve Optimiser.

Once in PBO under ‘AMD Overclocking’ you will see just one option set to ‘AUTO’. Change this to ‘Advanced’ and all other sub menu items will be revealed including the Curve Optimiser menu.

APPLYING THE OFFSET

Follow the steps above to find the Curve Optimiser menu option, enter your offset as desired, then return to the main PBO menu and set ‘Precision Boost Overdrive’ back to ‘AUTO’. All PBO settings return to default, the sub menus all disappear and become inaccessible – however your previously applied Curve Offset remains in place – it’s just hidden again.

 

[NoddyPirate]

BCLK OVERCLOCKING

BCLK stands for Bus Clock. The typical default BCLK frequency is 100 MHz.

When your CPU operates at a particular frequency, say 4.5 GHz for example, it isn’t being asked to operate at that frequency directly, but rather at a multiple of the BCLK frequency. This is what’s called the ‘multiplier’ or ‘core ratio’. So, a 4.5 GHz CPU is actually operating at a ratio of 45x over the BCLK of 100 MHz.

Manual Overclocking takes control of this multiplier or ratio and allows the CPU to operate at higher frequencies. So a stock 4.5 GHz CPU can be pushed to 4.725 GHz by changing the multiplier, or ratio, from 45x to 47.25x.

However you can also find the same frequency by increasing the BCLK. Changing the BCLK from 100 MHz to 105 MHz gives the same result as above (because 105 multiplied by the original ratio of 45x gives 4725 MHz = 4.725 GHz).


THE PROBLEM WITH BCLK AND PBO

Simple really – changing the BCLK frequency from it’s default value in BIOS with Ryzen CPU’s ignores all PBO settings and forces the system into a Manual Overclock mode. The Core Ratio returns to the default Base Clock for that CPU – on the 5600X this is 37x. So, you’ll lose all the benefits of PBO and gain all the inadequacies of manual overclocking in the process.

 

[NoddyPirate]

THE PROBLEM WITH BCLK OVERCLOCKING IN GENERAL

Changing the BCLK frequency doesn’t just affect the CPU. The Bus Clock determines the speed that all peripherals – such as PCIe components, M.2 Drives, RAM, Chipset, etc., operate at. It is effectively the communications speed control for your entire motherboard. So for example, increasing the BCLK from 100 to 105 will also force your 3600 MHz RAM DIMMs to Overclock to 3780 MHz.

While this might sound great, it means that instability when overclocking could actually be caused by any of your peripherals failing to keep up. Each change to the BCLK will require a full stress and stability test of your CPU, your RAM, your GPU, your SSD’s and HDD’s, and so on to ensure stability before you change anything else.

My experience is a perfect example of how messy this can all get:

Changing my BCLK to 102 was unstable – this was almost certainly because I had already overclocked my RAM from 3000 MHz to 3200 MHz. The BCLK increase pushed it to 3264 MHz which was likely a step too far.

To avoid this, I would have to reduce my RAM overclock to 3133 MHz – so that the higher BCLK frequency would see it operating at - 3133 x (102/100) = 3195 MHz – which is close to where the RAM was previously. And then I would have to go back and try it all again and see if was stable. Honestly, even with my OCD and general interest in learning new things, I just couldn’t be bothered!

 

[NoddyPirate]

THE PROBLEM WITH BLCK AND YOUR ENTIRE SYSTEM

Much more importantly, BCLK Overclocking applies more stress to all these peripheral components at the same time. Your chipset temperature will increase for starters, we’ve seen that your RAM might fail, but your drives might also suffer a fault and fail also. If this was to happen while an important write operation was in progress, then the consequences could be quite severe. There are multiple reports out there of complete and unrecoverable drive failure linked to BCLK changes. I have no idea if they are true or high likely any of this is, but I have no interest in finding out directly.

So, the advice from this rookie enthusiast at least – is just don’t touch BCLK overclocking with AMD. Any gains you might realise will probably be small and not worth the risk. Leave it at default and trust it.

______________________________________________

FINAL WORD AND FOOTNOTE

Enabling D.O.C.P on AMD platforms or XMP on Intel, uses information from the RAM’s SPD (Serial Presence Detect) information to allow your RAM to achieve the speed advertised on the box.

On some platforms however, enabling these profiles may significantly increase the BCLK above the default 100 MHz in order to achieve the desired RAM speed. This will also overclock your CPU and all connected peripherals – potentially causing instability and issues if other settings are not adjusted to compensate.

This may well be the reason that Intel do not cover the use of RAM XMP profiles under their standard warranty and consider it overclocking. Not every XMP profile will affect your BCLK mind you - many will leave the 100 MHz BCLK frequency unchanged and these won’t affect your CPU or bus connected devices. But caution is advised nonetheless.

 

[NoddyPirate]

WHY USE BCLK OVERCLOCKING AT ALL?

I realise now that adding BCLK into this thread might have seemed a bit out of context and perhaps the potential benefit of BCLK Overclocking, and why anyone would do it in the first place, might have been lost. So a quick explainer might be worthwhile:

BCLK OverClocking may be worth contemplating when it comes to locked (non K or X) Intel CPU’s. The core multiplier is locked on these Chips but adjusting the BCLK can still allow effective overclocking - assuming your motherboard allows it of course. And having control over VCore would be a must for this process too.

But in more general use, BCLK Overclocking would normally be the last bit you would do after Manually Overclocking the traditional way. You leave it till last because it is most likely to introduce instability, but also because it is potentially useful as a final tweak to refine your settings when you are trying to squeeze every last bit of performance out of your Overclock. To explain, here's another example:

Most Motherboards allow for x 0.25 increments on Core Ratio or Multiplier - such as 42.00, 42.25, 42.50, etc, etc. With a standard 100 MHz BCLK this would give clock speeds 25 MHz apart - 4.200 GHz, 4.225 GHz, 4.250 GHz, etc, etc.

So, let's say I can get a stable overclock at 4.250 GHz (42.50 ratio) but not at the next increment up from that which would be 4.275 GHz (42.75 ratio). By adjusting the BCLK I can effectively achieve clock speeds in between these ratios with some basic maths:

Using a 40.50 ratio but with a BCLK of 105 gives me a clock speed of 4.252 GHz, or
41.75 ratio with BCLK of 102 gives 4.258 GHz
41.00 ratio with BCLK of 104 gives 4.264 GHz
42.25 ratio with BCLK of 101 gives 4.267 GHz

These give me access to four more clock speeds that I couldn't achieve using the core ratio alone. I may be able to get one of these to remain stable and therefore squeeze a little more out of my system. Worth the effort? That all depends on what you're trying to achieve I guess!

The same effect would apply to RAM Overclocks:

With a BCLK of 100, my 3000 MHz RAM is stable at an Overclock of 3200 MHz, but not at the next standard frequency up the RAM speed table which is 3266 MHz. If I keep my RAM at 3200 MHz, but up the BCLK to 101, then I can effectively run it at 3232 MHz - which might work fine. Again, worth the effort? Probably not with RAM, but hey, it's fun to try!

As mentioned already in an earlier post, you can see that this whole thing gets really complicated, really quickly. Every time I change the BCLK, I will have to change both my CPU ratio AND my RAM speed (and possibly even peripheral clocks too) or I'll have trouble on my hands - just to show this with the examples in this post:

Go back to my first example of finding an in between frequency with my CPU Overclock - at 40.50 ratio and a BCLK of 105. If I don't change my 3200 MHz RAM speed when I do this, it will get overclocked to 3360 MHz. I'd need to reset my RAM speed back to a lower speed so that it continues to run properly at the new BCLK - such as 3000 by (105/100) = 3150 MHz, or perhaps 3066 by 105/100 = 3219 MHz if I think that will still work OK.

The final benefit that BCLK can give you is it may allow you to achieve a higher frequency at the same voltage than is possible using the multiplier alone, by allowing you to do drop the multiplier. So perhaps if 100 BCLK x 45.00 ratio = 4.5 GHz at 1.4 V is all you can achieve - you might be able to get 102 BCLK x 44.50 ratio = 4.539 GHz stable at the same voltage. Trial and error is the only way to find out. This also means that you may possibly be able to achieve higher overall overclocks when using BCLK than without it.

So, remebering that using BCLK only makes sense for Manual Overclocks which don't really suit Ryzen 3rd Gen CPU's anyway - add in the complication and system wide instability that can result - and you'll see why I wouldn't recommend it - unless you have a need to squeeze every last drop of performance out of RAM or Processor speeds - in which case you will have a lot of fun!!!