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Can't get 6400MT

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dumpa

Member
Joined
Nov 19, 2002
Location
Iowa
Just built a new PC. The first time in more than 15 years. Got two sticks of Corsair Vengance 6400 DDRAM5 cl32 but I could only get the Intel XMP ones, due to AMD Expo being sold out. The board is a Gigabyte x870 Eagle with a Ryzen 9 9900X.

I assembled it and it posted just fine with "XMP1" profile. Got a Corsair Core XT controller and installed it. Rebooted once just fine. The next time I was forced to load optimized defaults. I did notice that even when it was showing 6400 it was with cl40.

It boots fine with optimized defaults.

I didn't overclock anything. I'm simply trying to get a stable build with, if possible, advertised speeds. Any idea on how to troubleshoot this? Or should I just return this ram and get an AMD Expo certified one. Hopefully the inventory situation is better vs Black Friday.

Thanks
 
Update bios to latest if not already done. You can use CPU-Z and check what profiles are in the ram. It might have EXPO already even if not advertised as such. Looking at my own ram, the EXPO and XMP settings are near identical, with one present in each not in the other.
 
Update bios to latest if not already done. You can use CPU-Z and check what profiles are in the ram. It might have EXPO already even if not advertised as such. Looking at my own ram, the EXPO and XMP settings are near identical, with one present in each not in the other.
I actually did that but it looks like the update was solely geared towards the new 9800x3d which was just rubbing it in my face (since I couldn't get one). So I downgraded while troubleshooting.

The ram is in slots 2 and 4. I actually narrowed it down to "xmp/expo high bandwidth support" and that needs to be off. XMP1 profile loaded, with this setting off, seems to work fine. CPU-Z shows 6400MT with cl32.

BTW where there always this many cables!? It seems there are more of them now. Like why should there be three cables for a 4080? I'm only using 2 with a daisy chain on the 3rd one.


I can positively say this will be the last time I build a PC.
 
The ram is in slots 2 and 4. I actually narrowed it down to "xmp/expo high bandwidth support" and that needs to be off. XMP1 profile loaded, with this setting off, seems to work fine. CPU-Z shows 6400MT with cl32.
That's overclocking (at least, not 'just XMP' - I dont recall that enabled by default)... makes sense. Would have been great to know out of the gate. :)

I can positively say this will be the last time I build a PC.
LOL, really? A bit of adversity and....... no mas? :(
 
That's overclocking (at least, not 'just XMP' - I dont recall that enabled by default)... makes sense. Would have been great to know out of the gate. :)


LOL, really? A bit of adversity and....... no mas? :(
LOL I'm too old for this! Plus $2850 for a PC!? I remember the times when $500 for a GPU was a LOT!
 
LOL I'm too old for this! Plus $2850 for a PC!? I remember the times when $500 for a GPU was a LOT!
I hear ya... but that's half the fun in it, or at least was, LOL! I can understand you want to take things out of a box and have it just work though. :)

There's a premium on prebuilts making it even more expensive... can't win.
 
I hear ya... but that's half the fun in it, or at least was, LOL! I can understand you want to take things out of a box and have it just work though. :)

There's a premium on prebuilts making it even more expensive... can't win.
Wait a minute! The thing you said before. My memory was advertised as 6400! Does that mean I need to overclock it to get the advertised speed? Hmm I'm way too deep LOL

Thanks for your help
 
Wait a minute! The thing you said before. My memory was advertised as 6400! Does that mean I need to overclock it to get the advertised speed? Hmm I'm way too deep LOL

Thanks for your help
Sort of. When you enable XMP profile and it's past the platform's highest rated speed (like you are) you're overclocking the IMC, but not the sticks (sticks are rated for that speed).
 
I actually narrowed it down to "xmp/expo high bandwidth support" and that needs to be off. XMP1 profile loaded, with this setting off, seems to work fine.
Never heard of that before. In a quick search, it seems to be a feature of Gigabyte boards. They're trying to add "value" a bit like the old MCE era. I really wish they describe exactly what each setting does, rather than at best a vague description. If not enough room on bios screen then stick it in the manual. But they maybe don't want to do that as it'll be easy for other mobo manufacturers to copy directly.
 
Never heard of that before. In a quick search, it seems to be a feature of Gigabyte boards. They're trying to add "value" a bit like the old MCE era. I really wish they describe exactly what each setting does, rather than at best a vague description. If not enough room on bios screen then stick it in the manual. But they maybe don't want to do that as it'll be easy for other mobo manufacturers to copy directly.
Yeah never heard of it either. I was hoping to get the advertised speed without overclocking anything (at least not for now). I figured XMP is just a faster profile without overclocking (vs "fail-safe" optimized defaults), if that makes any sense.
 
XMP and now EXPO are relatively safe. It is still technically a form of overclocking but pretty much generally accepted at this point. It's what Gigabyte did on top of that which isn't clear.
 
Never heard of that before. In a quick search, it seems to be a feature of Gigabyte boards. They're trying to add "value" a bit like the old MCE era. I really wish they describe exactly what each setting does, rather than at best a vague description. If not enough room on bios screen then stick it in the manual. But they maybe don't want to do that as it'll be easy for other mobo manufacturers to copy directly.
ASRock also has something similar, or was it MSI? But yeah. I can't recall the option in the BIOS... maybe @Woomack can...?
 
Gigabyte mobos have high bandwidth and low latency modes. Both help in performance, and I haven't seen them cause problems at 6400. Biostar has only the high bandwidth mode; ASRock doesn't. I had no MSI to check it. ASUS had something similar, but I don't have one running to check right now.

6400 1:1 does not always work stable. It often works, but sometimes, the memory controller or motherboard can't handle it. If you can't make it work, then drop it to 6200 (enable XMP/EXPO and set the memory clock manually at 6200) and enable high bandwidth+low latency modes, as this will give you better performance in general. If disabling these additional options work for you, then you can also go this way, but maybe it requires a BIOS update or something.

In my X870E Pro ICE review, I mentioned better memory performance on Gigabyte motherboards. Here is the link to the AIDA64 comparison at 6400 1:1 so you can see the difference. The link to the ASRock X870E Taichi Lite review is just because there are more motherboards on the list.
 
Had a look on my Asus B650E bios. Don't seem to have anything like that there. The description has:
EXPO I - Asus messes with the settings
EXPO II - use actual EXPO settings (what I set)
EXPO on the fly - can't select this, dynamic mode?
EXPO Tweaked - can't select this - Asus does different messing around depending on IC?
AEMP - can't select this - Asus guesses if there is no profile?

No other settings I can see relevant in the area.
 
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