X370 Pro and BCLK.

hello, I need an answer for this too.
I'm thinking to buy an AM4 motherboard for my next rig, and seems that Asus Crosshair VI Hero work better with increase bclk. but, like I'd like to buy an asrock this time, I'd like to know why increase bclk doesn't work well on asrock.
bios problem ?
does hyper bclk engine 2 "desynchronise" bclk and pcie (sata, etc.......)
thanks well for your answer to redemp.

floyd


Edited by floyd - 27 Mar 2017 at 5:59am

I'm having the same problem with the ASRock X370 Taichi.

I bought a Taichi because it can ajust BCLK to O/C my DDR4 that is blocked at 2666MHZ because on ryzen 16Go sticks of DDR4 can't go higher :/


Edited by jonjojo007 - 27 Mar 2017 at 4:41pm

Yes, BCLK OC important to achieve high results... and one of the reasons why this board is bought (advertised Hyper BCLK Engine II with 136mhz). So, it`s fake? If people put 108 and get problems. Or is it a flaw in the bios?

As far as I know, whether or not the BCLK of a system's architecture is connected or not connected to all of the various system buss's (processor cores and PCIe, memory, chipset PCIe) is determined by the system's basic architecture. Meaning that cannot be changed by the mother board manufacture. There might be methods of doing that with extra circuitry that somehow isolates the PCIe buss in the CPU from the internal BCLK signal.

For example, the Intel Z170 and Z270 chipset platforms have the internal BCLK signal not connected to the various PCIe buss in the CPU and chipset. That is not the case for earlier Intel platforms like X99, Z97, etc. The Z170 and Z270 platforms allow CPU and DRAM memory over clocking with the BCLK, without affecting the PCIe clock.

As far as I know, the standard Ryzen architecture uses one BCLK signal that is shared with all the system's buss, including PCIe. If it is possible, as has been said is being done on an Asus Ryzen board, to separate the PCIe buss from the standard BCLK architecture, I have not researched that enough to know if that is true or not.

The external BCLK generator (Hyper BCLK Engine II) as used on the X370 Taichi is a separate chip for generating the BCLK signal, and is used instead of the internal BCLK signal generator built into the processor, or processor/SOC in the case of Ryzen. This chip creates a wider frequency range BCLK signal than the internal BCLK generator built into the system's architecture. The BCLK signal from this chip is used instead of the standard Ryzen BCLK signal generator.

All that is happening with the Hyper BCLK Engine II is instead of the internal BCLK generator, the external Hyper BCLK Engine II chip's signal is used instead. That does not change which system's buss use that signal, only the generation of that signal.

The X370 Taichi board does not seem to be able to isolate the PCIe buss from the BCLK signal created by the Hyper BCLK Engine II. So any increase in the BCLK frequency beyond the standard 100MHz will affect device using the PCIe lanes from the processor and chipset. If an Asus board can do that, it has special circuitry that allows that to happen. I did not see anywhere in the information for the Crosshair VI Hero that was used in the example above, where their external BCLK generator is isolated from the PCIe buss. What drives were being used in the example above?

M.2 NVMe SSDs use PCIe lanes from the Ryzen processor. All NVMe SSDs currently contain their own NVMe controller built into the SSD. The SATA controllers we have been using for years are built into the mother board's chipset,. In the case of a Ryzen processor being an SOC type, the processor itself contains the SATA controller.

The NVMe controller in M.2 NVMe SSDs is very sensitive to the BCLK frequency, it prefers a stable 100MHz signal, +/- a very small variation. Anything more than +2 - +4 MHz will cause instability in the NVMe controller, and cause the M.2 SSD to not work correctly. That's why we have problems booting them when the BCLK is too far from the standard 100MHz frequency.

Since the SATA controller in a Ryzen system also uses the BCLK, its stability will also be affected by changes to the BCLK frequency. That of course will cause issues with SATA drives.

Here's what I've found works for setting a REFCLK of so far up to 145 on my Killer SLI/ac

1. Put the graphics card into the PCIE4(x8) slot. A must.

2. When upping DRAM Ratio watch VERY closely that you don't go overboard with the OC. (parsec, it's exactly like when we talked on the phone concerning gonzo CPU MHz results on my OCF)