Ryzen 5000 Series Overclocking Options



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!!! :)
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