Corsair Vengeance DDR4 2666 LPX and HW monitor: R DIMM temps real?

[magellan]

I'm running Corsair Vengeance DDR4 2666 (@ 3086 MHz.) on my Asrock x99 Extreme 4 Haswell-E rig.

I've noticed in HW monitor that the DIMM temps for my Corsair Vengeance DDR4 2666 (@ 3086 MHz.) change over time. Is HW monitor actually reading a real temp sensor on these DIMM's?

If it's actually reading the temps of the DIMM's what kind of maximum temps should a DDR4 DIMM be subject to? I'm seeing maximum temps of around 38 degrees C.

I'm only now getting a stable o'clock on this system which is why I haven't updated my sig.

 

[EarthDog]

I do not know if memory has sensors on them. I never bother to monitor them because they run so cool. Its not until you get into raising the volts A LOT (talking .2v) that a heatspreder and some air movement is really needed. I wouldn't worry about it, but I am curious to hear an answer.

You should update your sig anyway... then just adjust the parts that need it when they need it. Otherwise, you have been hanging on to this signature for at least a few weeks when its not the hardware you have. Confusing (I think I mentioned to update your sig a couple of times already, lol!).

 

[Woomack]

Many DDR4 have thermal sensors and if any soft reads temps then it's probably correct. Most DDR4 even after overvoltage keep temps between 35-45*C. Crucials @1.5V under load had ~42*C. Max depends from modules but is something about 80-85*C for constant work. I wouldn't worry about temps as even without any fan and at high voltage it's not possible to reach it.

 

[magellan]

Many DDR4 have thermal sensors and if any soft reads temps then it's probably correct. Most DDR4 even after overvoltage keep temps between 35-45*C. Crucials @1.5V under load had ~42*C. Max depends from modules but is something about 80-85*C for constant work. I wouldn't worry about temps as even without any fan and at high voltage it's not possible to reach it.

Thanks Woomack.
What does the sensor monitor though? It doesn't monitor all the individual RAM IC's does it?

Your advice about o'clocking the Haswell-E has helped out a lot, but the one setting that was screwing me up all this time turned out to be the DRAM Reference Clock, which only has two settings 100 MHz and 133 MHz. The BCLK and DRAM Reference Clock settings have to somewhat match otherwise I get random lockups/crashes etc.

 

[Woomack]

Set DRAM Ref Clock to auto. On most motherboards auto works fine and sets correct value.
I'm not sure where is sensor on memory but I guess that somewhere near or under the IC as PCB itself is not heating up much.

 

[magellan]

Set DRAM Ref Clock to auto. On most motherboards auto works fine and sets correct value.
I'm not sure where is sensor on memory but I guess that somewhere near or under the IC as PCB itself is not heating up much.

The auto setting for DRAM reference clock on my Asrock X99 Extreme4? I tried that Woomack. I could never get any BCLK above 105 stable until I manually set the DRAM reference clock to 133 MHz.

 

[Woomack]

I'm talking about auto for 100MHz bclk and various memory ratios. If you pick memory frequency which is working only on 133 then board will automatically set it to 133. I'm not sure why anyone would OC bclk on these boards. There are so many ratios that you can set nearly the same without touching bclk.

It's normal that bclk may not work above some value as on these boards pcie is not locked. Some devices won't run stable, the same as on 130MHz+. Depends from board it can be +5MHz from each strap or a bit more.

I think we were talking about it couple of times in the past.

 

[EarthDog]

It's normal that bclk may not work above some value as on these boards pcie is not locked. Some devices won't run stable, the same as on 130MHz+. Depends from board it can be +5MHz from each strap or a bit more.

Or in other words, it is the same ~-5/+5 situation that holds true around all the straps... So 125 +/-5, 166 +/-5, etc....in essence, you are only changing the BCLK 5ish. The strap/gearing yields ZERO performance gains on its own as it is not affecting the other speeds attached to the bus.

 

[magellan]

I'm talking about auto for 100MHz bclk and various memory ratios. If you pick memory frequency which is working only on 133 then board will automatically set it to 133. I'm not sure why anyone would OC bclk on these boards. There are so many ratios that you can set nearly the same without touching bclk.

It's normal that bclk may not work above some value as on these boards pcie is not locked. Some devices won't run stable, the same as on 130MHz+. Depends from board it can be +5MHz from each strap or a bit more.

I think we were talking about it couple of times in the past.

On the Asrock x99 Extreme 4 the only way you can get the memory bus >= 3000 MHz is by using straps greater than 100 MHz.

 

[EarthDog]

Straps are not the same as actually overclocking your BCLK. I mentioned above that the only "real" BCLK overclocking is the -/+5 variance around each strap...

But yes, you are right, most(all?) boards that run 2800+ will adjust the strap to 125 in order for the memory multiplier to reach that speed.

Also, the 100/133 strap is for the memory. I have no idea if that changes, I leave it on auto. BUt that is different than the BCLK strap we are talking about (100/125/166).

 

[Woomack]

If you check available memory ratios on X99 then it will be:
x21.33 2133/2666
x22.00 2200/2750
x24.00 2400/3000
x26.66 2666/3333
x28.00 2800/3500 <== this one is not working on many boards
x30.00 3000/3750 <== this one is not working on many boards
x32.00 3200/4000

In XMP profiles 2800 is always as 22 x 127.3 bclk. 3000 is always as 24 x 125bclk.