[Solved] XMP no longer working after CPU RMA

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nimbulan

n00b
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Jun 15, 2020
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So a bit of a strange situation here. I recently RMA'ed my CPU - yes I actually had a defective chip. Since I got the replacement, it's been nearly impossible for my system to POST with XMP enabled. With the old defective CPU, I had zero issues using XMP (and was never able to produce a single memory error when testing.) The only thing that's changed in the system is plugging in the new side panel fan and a new CPU heatsink though I'm using the same fan on it as the old one.

The BIOS will reboot repeatedly to retry setting the RAM timings, or even sometimes seemingly pass validation and display the splash screen, only to reboot again after a couple seconds. If I can actually get it booted (and I did manage to load XMP once) it's perfectly stable. This seems to mostly be a problem with cold booting, it's more likely to boot the longer the PC has been on.

I have tried manually setting the timings to match the XMP profile, increasing the DRAM voltage, and doing some manual adjustments after letting it auto some of the timings. Even setting it to 3200 MHz 1.35V and leaving every timing on auto does not successfully boot on the first try, and results in incredibly poor timings when it does boot.

I discovered DRAM Calculator this morning and calculated timings for my system, and it's giving me significantly lower timings than even my XMP profile. I'm pretty certain it won't boot with these, so what do I do? Did I somehow manage to get another faulty CPU?

Hardware:
Ryzen 3700x
ASRock x570 Phantom Gaming 4
4x8GB Crucial Ballistix 3200 MHz 16-18-18-36
Corsair RM650x power supply
GTX 1070

Solution: In the BIOS, change VDDCR SOC Voltage to offset mode, and increase it by one increment (6.5 mV.)
 
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nimbulan said:
So a bit of a strange situation here. I recently RMA'ed my CPU - yes I actually had a defective chip. Since I got the replacement, it's been nearly impossible for my system to POST with XMP enabled. With the old defective CPU, I had zero issues using XMP (and was never able to produce a single memory error when testing.) The only thing that's changed in the system is plugging in the new side panel fan and a new CPU heatsink though I'm using the same fan on it as the old one.

The BIOS will reboot repeatedly to retry setting the RAM timings, or even sometimes seemingly pass validation and display the splash screen, only to reboot again after a couple seconds. If I can actually get it booted (and I did manage to load XMP once) it's perfectly stable. This seems to mostly be a problem with cold booting, it's more likely to boot the longer the PC has been on.

I have tried manually setting the timings to match the XMP profile, increasing the DRAM voltage, and doing some manual adjustments after letting it auto some of the timings. Even setting it to 3200 MHz 1.35V and leaving every timing on auto does not successfully boot on the first try, and results in incredibly poor timings when it does boot.

I discovered DRAM Calculator this morning and calculated timings for my system, and it's giving me significantly lower timings than even my XMP profile. I'm pretty certain it won't boot with these, so what do I do? Did I somehow manage to get another faulty CPU?

Hardware:
Ryzen 3700x
ASRock x570 Phantom Gaming 4
4x8GB Crucial Ballistix 3200 MHz 16-18-18-36
Corsair RM650x power supply
GTX 1070
Click to expand...
ever single set of corsair ive ever used, ever, needed extra voltage. bump it to 1.4v and see if that gets it stable. if not then just manually set the speed/timing based on what the xmp setting are.
oops, guess i needed to read closer. try loosening the timings a bit. like 17-19-19-19
 
pendragon1 said:
ever single set of corsair ive ever used, ever, needed extra voltage. bump it to 1.4v and see if that gets it stable. if not then just manually set the speed/timing based on what the xmp setting are.
oops, guess i needed to read closer. try loosening the timings a bit. like 17-19-19-19
Click to expand...
Yeah I already tried 1.4V and it didn't seem to make any difference whatsoever. I can certainly try those timings, though my experience has been that auto-ing the rest of them is still iffy and it seems to be having the most trouble with the RAS timings. And then even if it works now, it likely won't work tomorrow morning (which is what happened to my tweaks yesterday.) I can't for the life of me figure out why that even matters.
 
have you done a good long battery out cmos clearing? bios is up to date?
 
pendragon1 said:
have you done a good long battery out cmos clearing? bios is up to date?
Click to expand...
Actually looks like ASRock just released the new BIOS to support the XT CPUs. I don't know what other changes are in there but it's worth a try.

I was just able to get it to boot again with XMP enabled by enabling SOC/Uncore OC mode, a suggestion I found in another thread. It still took 2 tries to POST though so the problem is obviously not solved. I compared the suggested timings from DRAM Calculator with what it's currently running at and there are only two timings that DRAM Calculator recommends being slower, so I guess I'll start there the next time I tinker with it.

Edit: It also appears that this issue I'm having is not uncommon with modern Ryzen systems. Makes me miss Intel, oh well.
 
I recently built a new Ryzen based PC and ran into similar issues with my RAM when set to it's XMP/DOCP speeds. What fixed it for me was setting the VDDCR SOC Voltage to offset mode, +. I'm using an ASUS Prime x570-P so I'm not sure if the setting will be the same on your ASRock board.
 
GameLifter said:
I recently built a new Ryzen based PC and ran into similar issues with my RAM when set to it's XMP/DOCP speeds. What fixed it for me was setting the VDDCR SOC Voltage to offset mode, +. I'm using an ASUS Prime x570-P so I'm not sure if the setting will be the same on your ASRock board.
Click to expand...
I did see your reply in the other thread. What exactly do you mean by "offset mode, +"? Did you just bump it up by one increment (I think it's 6.5 mV)?
 
nimbulan said:
I did see your reply in the other thread. What exactly do you mean by "offset mode, +"? Did you just bump it up by one increment (I think it's 6.5 mV)?
Click to expand...
From what I remember there was a setting named "VDDCR SOC Voltage" and it was disabled at first. After enabling it it gave me more options below it and one was called "Offset" or maybe "Offset Mode" and it was set to "+" by default. So, essentially all I did was enable the VDDCR SOC Voltage and the default settings were what I needed.
 
GameLifter said:
From what I remember there was a setting named "VDDCR SOC Voltage" and it was disabled at first. After enabling it it gave me more options below it and one was called "Offset" or maybe "Offset Mode" and it was set to "+" by default. So, essentially all I did was enable the VDDCR SOC Voltage and the default settings were what I needed.
Click to expand...
Looking at the manual for your motherboard, it seems there are two separate options for offset sign, and offset voltage. I'm not really sure why those are separate since it's just one setting on my board. I'll definitely look into tinkering with that if this new BIOS update doesn't help.

Edit: Updated my BIOS this morning, bumped the VDDCR SOC Voltage up by 6.5 mV with the offset feature, and it booted first try with XMP enabled. Will have to see if it works from a cold boot tomorrow morning.
 
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After the VDDCR SOC Voltage change yesterday, my system successfully booted first try this morning, so I'm going to call it problem solved. It's amazing how much of a difference a tiny voltage change can make. Thank you GameLifter for the suggestion.
 
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