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Overclocking RAM, additional suggestions requested (low priority)

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AceXMachine

New Member
Joined
Apr 29, 2020
Ok, I'm running a Gigabyte Aorus Z390 Master and my RAM is 4x8GB Corsair Vengence RGB Pro (CMW32GX4M4K4266C19) XMP: DDR4 4266 (PC4 34100) @ 19-26-26-46-1.45V

Now, I didn't exactly do enough research on this beforehand (I was anxious/excited to be building a new PC again) and think this particular kit may have been overpriced and/or just plain garbage, but what's done is done.

So what has happened so far:

I could not get this memory to run reliably using XMP, even with the values (which look like garbage to me now that I kinda know what I am looking at, please correct me if wrong) manually set in BIOS

Decided to bump down to DDR4000 and go with tighter timings instead. Currently running:

CAS Latency tCL: 16
RAS to CAS delay tRCD: 18
Row Precharge Time tRP: 18
RAS Active Time tRAS: 36
Command Rate CR: 2

Write Recovery Time tWR: 24
Refresh Cycle Time tRFC: 600
RAS to RAS Delay tRRD_L: 11
RAS to RAS Delay tRRD_S: 9
Write to Read Delay tWRT_L: 19
Write to Read Delay tWRT_S: 13
Read to Precharge tRTP: 12
Four Activate Window tFAW: 47
CAS Write Latency tCWL: 16
tREFI: 32000

There are more of course but I know nothing about those and it seems that those should basically be left on Auto. Of those settings I listed, I changed the "main" timings from the default JEDEC/XMP to the 16-18-18-36 and I changed the tRFC from some rediculously high number to 600 (may try pushing that even lower) and the tREFI to 32000 (may try pushing that higher) since I basically know what those 2 do. The rest are pretty self explanatory but being that I've never done this before I don't know where to go from here.

I know that 16-16-16-36 is NOT stable and don't know if it is worth it to try bumping the voltage to get it stable as I am already at 1.45V?

What I'm asking is, with this info (if more is needed let me know), where would you go from here to try to squeeze more performance from these chips? Are there any general "rules of thumb" I may not have gotten having not been into overclocking until recently (IE: is it a big deal not to have tCL match tRCD/tRP? How much, if any, timings should I sacrifice to get 1T CR?) Was my approach of dropping 266MHz to go from 19-26-26-46 to 16-18-18-36 worth it (benchmarks seem to indicate it was)?

As I indicated in the subject this is low priority but I am open to any suggestions on my current setup. I've crammed a lot of research into this these last few weeks but I feel I've gone as far as I can safely go without some practical experience to guide me further. I am an IT professional (Obviously not in overclocking) so you don't have to worry about dumbing it down TOO much ;)

Thanks for listening!
 

Johan45

Benching Team Leader Super Moderator
Joined
Dec 19, 2012
To be honest if what you have now is stable then you may as well go with it. Unless you are benchmarking competitively spending a lot of time tuning RAM isn't going to pay off. The performance gain really isn't worth it.
I have spent countless hours doing it myself for benching but my 24/7 machine needs to be stable and squeezing that 1% isn't worth it to me.
 
OP
A

AceXMachine

New Member
Joined
Apr 29, 2020
To be honest if what you have now is stable then you may as well go with it. Unless you are benchmarking competitively spending a lot of time tuning RAM isn't going to pay off. The performance gain really isn't worth it.
I have spent countless hours doing it myself for benching but my 24/7 machine needs to be stable and squeezing that 1% isn't worth it to me.

Oh yeah, I'm perfectly fine with it. I'm just trying to get some practical experience with it and expand what I know and see what the next step is/would be
 

Johan45

Benching Team Leader Super Moderator
Joined
Dec 19, 2012
My best suggestion would be to try one timing at a time and test it. Use an OS that doesn't matter because you will eventually corrupt it. Same goes for the BIOS, I have corrupted them more than once tweaking memory. aside from the main timings, trc, trfc, thaw, can help but as I said test after each change sometimes the performance can drop
 

batboy

Senior Moment
Joined
Jan 12, 2001
Location
Kansas, USA
Like Johan said, RAM overclocking is not for the timid, and once you get to the fine tuning point of timings, it's not going to gain you much. That said, not sure if you've tried increasing voltage on VCCIO and SA (BIOS settings), but I've found that sometimes helps RAM stability. You might try 1.1v -1.15v on VCCIO and 1.05v - 1.10v on SA (assuming you have decent case ventilation).

I don't know much about the chipset you're using, but my motherboard just flat out won't run stable above DDR 4000. But, I'd rather run 4000 with tight timings than 4200 with loose as a goose timings.
 

Woomack

Benching Team Leader
Joined
Jan 2, 2005
The best is always a balance between memory bandwidth and latency. Usually ~4000 memory clock at tight timings is giving the best results. ~4000 mem clock on Z390 is not stressing memory controller much so you don't have to use high SA/IO voltages which are also causing the CPU to heat up more.
There is no platform that is scaling well past ~4000 mem clock so for 24/7 use it's better to set 4000 and tighter timings than try to set higher memory clock at more relaxed timings (which will be required to keep memory stable).
 
OP
A

AceXMachine

New Member
Joined
Apr 29, 2020
Like Johan said, RAM overclocking is not for the timid, and once you get to the fine tuning point of timings, it's not going to gain you much. That said, not sure if you've tried increasing voltage on VCCIO and SA (BIOS settings), but I've found that sometimes helps RAM stability. You might try 1.1v -1.15v on VCCIO and 1.05v - 1.10v on SA (assuming you have decent case ventilation).

I don't know much about the chipset you're using, but my motherboard just flat out won't run stable above DDR 4000. But, I'd rather run 4000 with tight timings than 4200 with loose as a goose timings.

Yeah, that's basically why I am getting into it. Always before I either didn't have the time, equipment (money) to bother with tweaking and overclocking. I do a bunch of IT work so I'm pretty sure I can fix anything I break unless I actually fry something.

VCCIO and SA have been bumped but I can't recall ATM what exactly I set it to. But it definitely did not like 4266 even with XMP settings (auto or manual). I'm perfectly happy with what I got now at 4000 I'm just wondering what the next logical step is. Assuming I can't get better than 16-18-18-36 stable, which setting would be "next in line" to tweak first. Truth Is that since getting this working at 4000-16-18-18-36 I've been too lazy to try anything else. Gonna have to wait til I get bored again before I try squeezing any more out of these things. Chipset is intel Z390 Master from Gigabyte.


The best is always a balance between memory bandwidth and latency. Usually ~4000 memory clock at tight timings is giving the best results. ~4000 mem clock on Z390 is not stressing memory controller much so you don't have to use high SA/IO voltages which are also causing the CPU to heat up more.
There is no platform that is scaling well past ~4000 mem clock so for 24/7 use it's better to set 4000 and tighter timings than try to set higher memory clock at more relaxed timings (which will be required to keep memory stable).

That has been my assessment as well. I would have thought that this board could handle it but either the memory was a bit ambitiously advertised or, like you said, no platforms work well past 4000. Based off some the benchmarks I've run, its doing about 10-12% better at 4000 with these timings when at 4266 with XMP timings (when I could actually get it to work at that) and I'm quite happy with it. Just basically playing around with it now, especially since I'm going to be reinstalling Windows soon and want to get all the crazy stuff out of the way before I do.
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
It's the platform...you just overbought on the sticks. Maybe with z490 and the new chips though.. ;)
 

Woomack

Benching Team Leader
Joined
Jan 2, 2005
On the other hand, 4266 kits at more relaxed timings are based on the same IC as 4000 and tighter timings while 4266 kits are generally cheaper.
If you used two 8GB memory modules then I guess you could go up to 4500+ mem clock. 4 memory sticks make some problems with higher OC. It still should work at XMP but may require some manual adjustments. I also don't really know how Gigabyte Z390 motherboards are acting so it's hard to give any advice. I'm usually overclocking on ASRock or ASUS.
Anyway, as you already noticed (and some others confirmed) DDR4-4000 at tighter timings is pretty much the best option for you.

Most gaming/overclocking series motherboards have guaranteed memory support up to ~4266 but many will support 4133+ using only two memory modules. The best motherboards, with official DDR4-4500+ support, have usually 2 memory slots.
Saying about memory scaling I mean more that performance is not really increasing after you pass ~4133 because you can't keep the optimal balance between mem bandwidth and latency. It's a matter of memory controllers but probably we will see DDR5 faster than a good reason to use DDR4 at 4500+.