Memory speed troubles

[MedicBoi]

I recently built my first computer consisting of 

Motherboard: Aorus X570 Elite Wifi

CPU: Ryzen 7 3800x
Memory: Corsair Vengeance RGB Pro 16GB (2x8GB) 3600 MHz C18 (CMW16GX4M2Z3600C18)

GPU: XFX RX 5700 XT Thicc III Ultra

SSD: Aorus NVMe Gen 4 500 GB 

PSU: ThermalTake Toughpower Grand RGB

 

My issue is getting optimum memory speeds. After getting everything set up and running, I enabled the XMP which appeared to change the values in the BIOS. After rebooting I found the memory continued to run around 2666 MHz, although the 1.35V was applied. Checking in windows all of the SMP timings remained. I tried entering all the values from XMP manually with massive instability. Sometimes I wouldn't post, sometimes the BIOS would reset, and if I managed to get into windows it continued to run at 2666 MHz, or would crash. Being that I dropped a decent chunk of money on a new AMD CPU and high frequency memory, I would like to get the performance I paid for. Does anyone have any advice on getting the advertised speeds out of my memory?

[Newbygeek]

What ram slots are you using? If it’s A1 & B1, try a2 with b2 since it’s recommended by Mobo manufacturers. 

And what are the values that xmp writes to bios?

[Jurrunio]

Try run 3200MHz first, maybe it's just too unstable for 3600MHz.

[MedicBoi]

I'm using A2 and B2 as recommended by the board. 

The values are 1.35V, 36.00 multiplier, and 18-19-19-39 for timings.

[Jurrunio]

3 minutes ago, MedicBoi said:

The values are 1.35V, 36.00 multiplier, and 18-19-19-39 for timings.

Ryzen verified kits often take 18-22-22-42 instead so you could also try loosening it

[MedicBoi]

Just now, Jurrunio said:

Ryzen verified kits often take 18-22-22-42 instead so you could also try loosening it

I'll give that a shot once I get home from work.

[aDoomGuy]

Check the SPD information for the XMP memory timings and verify that all the timings are set. I had to set some subtimings manually... 

[Newbygeek]

1 hour ago, Jurrunio said:

Ryzen verified kits often take 18-22-22-42 instead so you could also try loosening it

It’s a weird situation because if this xmp profile is not compatible with this Mobo, the why does it even boot up?? Mobo must beep instead

[Jurrunio]

1 minute ago, Shervan said:

It’s a weird situation because if this xmp profile is not compatible with this Mobo, the why does it even boot up?? Mobo must beep instead

that's wrong, instability does not have a clear cut-off point. It could crash/reset after posting.

[Newbygeek]

1 minute ago, Jurrunio said:

that's wrong, instability does not have a clear cut-off point. It could crash/reset after posting.

I know but He is saying that he sets 3600mhz in bios and Windows boots with 2666.

[Jurrunio]

1 minute ago, Shervan said:

I know but He is saying that he sets 3600mhz in bios and Windows boots with 2666.

posting and booting into an OS are different things. For Ryzen, the procedure is: AGESA initialize --> BIOS loads --> Boots OS from boot drive. It could very well crash before it managed to boot, so it rolls back to previous phases with the last stable setting (or whatever the SPD profile has that's JEDEC spec) and manages to boot.

[Newbygeek]

1 minute ago, Jurrunio said:

posting and booting into an OS are different things. For Ryzen, the procedure is: AGESA initialize --> BIOS loads --> Boots OS from boot drive. It could very well crash before it managed to boot, so it rolls back to previous phases with the last stable setting (or whatever the SPD profile has that's JEDEC spec) and manages to boot.

It must’ve been 2133 if it crashed. All the boards reset the frequency to 2133 which is the least for ddr4

[Jurrunio]

2 minutes ago, Shervan said:

It must’ve been 2133 if it crashed. All the boards reset the frequency to 2133 which is the least for ddr4

Then you havent tested enough memory kits. This appears to be true just because most kits rated above 2666 will have 2133MHz CL15 profile as its second fastest speed in the SPD chip, which is what boards are programmed to try. If such kit has a 2666MHz CL19 profile at the same time (SPD chips usually hold up to 4 profiles, including the one only available through XMP) then the board would try 2666MHz CL19 first

[Newbygeek]

3 minutes ago, Jurrunio said:

Then you havent tested enough memory kits. This appears to be true just because most kits rated above 2666 will have 2133MHz CL15 profile as its second fastest speed in the SPD chip, which is what boards are programmed to try. If such kit has a 2666MHz CL19 profile at the same time (SPD chips usually hold up to 4 profiles, including the one only available through XMP) then the board would try 2666MHz CL19 first

I didn’t know thanks

[MedicBoi]

So I checked and did some testing without much luck. The XMP timings were in fact 18-22-22-42. I tried setting those manually and starting at 3200. At 3200 I would occasionally get it to load to that speed, although it often reverted back to the SPD or even reset the BIOS a few times.