Question RAM wont overclock on B450 board in A1 and B1 slots

majere613

Commendable
Jan 11, 2019
5
0
1,510
0
I have a ASUS ROG Strix B450-F Gaming, Ryzen 2700x. Until recently I was running two 8GB sticks of Corsair Vengeance DDR4 in the A2 and B2 slots, overclocked to 3200 using the board's 'AI Tweaker'.

I've now upgraded by adding two more 8GB sticks of the exact same RAM, in the A1 and B1 slots to fill all 4 slots on the board. After doing this, the machine reset when turned on and sent me to BIOS with a message saying my memory settings had been reset due to failure to boot.
After some testing, I've confirmed:
The machine will boot with 4 sticks if the memory is clocked to 2666 or 2700, but won't hit 2800 or higher.
This behaviour is the same if only the A1 and B1 slots are populated, with both the old and the new RAM.
The memory will clock to 3200 if only the A2 and B2 slots are populated, with both the old and the new RAM.
Memtest86 seems to be testing all 4 sticks at 3200 and completes a full pass with no errors. It reports the same timings (16,18,18,36) as advertised for the RAM. I've not yet tried an extended test but it seems to me that RAM that passes a 1.5 hour long test should be stable enough to at least boot.

Things I've tried:
Specifically setting the board's overclock mode to DOCP applies a voltage boost to the RAM to 1.35 and sets the correct timings. No effect on the issue.
Manually upping the memory voltage to 1.4 has no effect on the issue.
BIOS update to the board to the most recent version has no effect on the issue.

Running at 2666 seems to be providing acceptable performance, and the machine is stable, but I'm at a loss to understand why two slots on the board should be having this problem, whilst at the same time not seeming to cause any problem for Memtest86.

Ideas would be appreciated, bearing in mind I'm not really a hard-core overclocker.
 
I have a ASUS ROG Strix B450-F Gaming, Ryzen 2700x. Until recently I was running two 8GB sticks of Corsair Vengeance DDR4 in the A2 and B2 slots, overclocked to 3200 using the board's 'AI Tweaker'.

I've now upgraded by adding two more 8GB sticks of the exact same RAM, in the A1 and B1 slots to fill all 4 slots on the board. After doing this, the machine reset when turned on and sent me to BIOS with a message saying my memory settings had been reset due to failure to boot.
After some testing, I've confirmed:
The machine will boot with 4 sticks if the memory is clocked to 2666 or 2700, but won't hit 2800 or higher.
This behaviour is the same if only the A1 and B1 slots are populated, with both the old and the new RAM.
The memory will clock to 3200 if only the A2 and B2 slots are populated, with both the old and the new RAM.
Memtest86 seems to be testing all 4 sticks at 3200 and completes a full pass with no errors. It reports the same timings (16,18,18,36) as advertised for the RAM. I've not yet tried an extended test but it seems to me that RAM that passes a 1.5 hour long test should be stable enough to at least boot.

Things I've tried:
Specifically setting the board's overclock mode to DOCP applies a voltage boost to the RAM to 1.35 and sets the correct timings. No effect on the issue.
Manually upping the memory voltage to 1.4 has no effect on the issue.
BIOS update to the board to the most recent version has no effect on the issue.

Running at 2666 seems to be providing acceptable performance, and the machine is stable, but I'm at a loss to understand why two slots on the board should be having this problem, whilst at the same time not seeming to cause any problem for Memtest86.

Ideas would be appreciated, bearing in mind I'm not really a hard-core overclocker.
Using both IMC channels by having 4 sticks of RAM restricts memory speed/frequency on any Ryzen before 5000 series.
 
Reactions: majere613

majere613

Commendable
Jan 11, 2019
5
0
1,510
0
Using both IMC channels by having 4 sticks of RAM restricts memory speed/frequency on any Ryzen before 5000 series.
Is it really that simple? I'm tempted to just accept it and move on, especially since I'm running soft-tubed in an O11D so it's fairly easy to just remove the sticks in the x1 slots if I need the extra speed back instead of the capacity. But it doesn't seem to explain why two slots on the board won't overclock even if they're the only two populated, whilst the other two will. Is it just that those slots can only run at the slower speeds by design, hence the x2 slots being the 'recommended' ones? The board manual doesn't seem to say anything more than that.
 
Is it really that simple? I'm tempted to just accept it and move on, especially since I'm running soft-tubed in an O11D so it's fairly easy to just remove the sticks in the x1 slots if I need the extra speed back instead of the capacity. But it doesn't seem to explain why two slots on the board won't overclock even if they're the only two populated, whilst the other two will. Is it just that those slots can only run at the slower speeds by design, hence the x2 slots being the 'recommended' ones? The board manual doesn't seem to say anything more than that.
If you look in MB's manual you will see that there are primary, usually A2 and B2 slots which connect to first IMC in the processor each one for a pair of RAM sticks for dual channel. The other two usually don't OC as good or even don't provide dual channel. That's problem with CPU architecture, That's solved in 5000 series Ryzen. IMC also gets overloaded when using 4 sticks in earlier Ryzen, also most Intel CPUs.
5000 series Ryzen on MBs with 500 chipset work even better with 4 sticks.
 

majere613

Commendable
Jan 11, 2019
5
0
1,510
0
If you look in MB's manual you will see that there are primary, usually A2 and B2 slots which connect to first IMC in the processor each one for a pair of RAM sticks for dual channel. The other two usually don't OC as good or even don't provide dual channel. That's problem with CPU architecture, That's solved in 5000 series Ryzen. IMC also gets overloaded when using 4 sticks in earlier Ryzen, also most Intel CPUs.
5000 series Ryzen on MBs with 500 chipset work even better with 4 sticks.
Well, that settles that then! I suppose I should be grateful I got as far as 2666. Rather than take up space, please imagine a He-man "knowing is half the battle" GIF.

Thanks to all who looked and replied!
 

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