[SOLVED] Using memory with different latency settings

[ssilverm]

* Update on the post below *

I've been running the mixed RAM for almost two weeks now, with no apparent problems. The applications are fairly memory-intensive, particularly Cubase used with dozens of virtual instruments loaded. Also lots of 4K video work, using DaVinci Resolve.

Everything seems absolutely fine. What am I missing? 🤔

* End of update *


I would like to add a further 32Gb of memory to a PC that I built last year, using 32Gb of Corsair Vengeance LPX Black 3200MHz RAM.

It appears that the spec, as far as latency settings are concerned, is now slightly different. The original RAM runs at 16-18-18-36, while the settings for the RAM available now are 16-20-20-38.

I'm guessing this isn't going to be a major issue, but I thought it best to check here first.

Thanks in advance

Steve

 

[Lafong]

The rubber won't meet the road until you actually attempt to use the new and old at the same time. Until then, guess, wonder, and speculate. Maybe, oughta, should, probably, probably not, etc.

Buying 64 new and selling the old 32 may be an option? Or not.

Make sure you can return the new RAM if it doesn't work?

10 years ago, it seems to me that you had a pretty good chance of it working out if voltages and timings were close. Nowadays, people are generally more fearful. I've never added RAM like that, so I don't know to what extend the fear is justified in actual practice. Maybe RAM has become so commoditized that manufacturers are straying from supposed standards and thereby causing more problems than a decade ago.

 

[Lutfij]

You might want to avoid working with two different spec'd near identical sticks of ram to avoid headaches and troubleshooting. Rams are tied to three things, latency, frequency and voltage, if one is off then you have instability. See if you can find the same kit as the one you own. If not, invest in a higher capacity kit and ditch the one you have to avoid mixing and matching kits/sticks of ram.

Make and model of your motherboard? BIOS version of said motherboard? Processor?

 

[mamasan2000]

The rubber won't meet the road until you actually attempt to use the new and old at the same time. Until then, guess, wonder, and speculate. Maybe, oughta, should, probably, probably not, etc.

Buying 64 new and selling the old 32 may be an option? Or not.

Make sure you can return the new RAM if it doesn't work?

10 years ago, it seems to me that you had a pretty good chance of it working out if voltages and timings were close. Nowadays, people are generally more fearful. I've never added RAM like that, so I don't know to what extend the fear is justified in actual practice. Maybe RAM has become so commoditized that manufacturers are straying from supposed standards and thereby causing more problems than a decade ago.

JEDEC is standardized but consumer RAM comes with XMP, which is outside JEDEC spec. There goes the standardized-part. So it's a headache if you mix RAM kits, even if it's the same model, same brand, same clocks AND same timings. Only thing that matters is what ICs are used and their characteristics. You can get singlerank or dualrank on top of that. And then your motherboard has to guess what settings and timings should work. Some motherboards are worse at this than others. Even then, you very likely have to go in and manually adjust a bunch of settings so you better know what you are doing and what all the timings mean and do. It's complicated.
10 years ago you had access to like 5 timings. Now it's something like 40-50 timings and settings. On top of that there are hidden settings the motherboard sets. You can't get access to those.

 

[Lafong]

Mamasan:

Thanks for that.

Can you hazard a guess?

If some non-expert on this forum makes a post or 2 about adding RAM, receives advice, and then takes some reasonable care to buy the closest possible matching RAM, what are his chances of success?

5%?

40?

80?

I'm just curious as we probably hear more about failures than successes.

As I said, I've never even tried it....but I have no idea how unlikely it is to succeed on current machinery.

 

[kerberos_20]

10 years ago you had access to like 5 timings. Now it's something like 40-50 timings and settings

hmm technically, even DDR1 20years ago had like 20 timing settings, which were mostly hidden from user on cheap mainboards
i used to have dfi mobo which had it all user changeable and DDR1 was kicking at 750MHz thanks to those timings...then it got burned few yers later on and mobo replacement (dont remember brand, bot some ecs?) had some timings not user changeable which limited overclock a lot as it couldnt be changed and mobo was selecting timings which wouldnt work at higher speeds

10years ago DDR3 was similar to DDR4 in ram settings, CAD/proc ODT settings were there aswell

 

[kerberos_20]

Mamasan:

Thanks for that.

Can you hazard a guess?

If some non-expert on this forum makes a post or 2 about adding RAM, receives advice, and then takes some reasonable care to buy the closest possible matching RAM, what are his chances of success?

5%?

40?

80?

I'm just curious as we probably hear more about failures than successes.

As I said, I've never even tried it....but I have no idea how unlikely it is to succeed on current machinery.

50% that it will work
CPU itself should run 3200MHz with 4 sticks
as for mainboard, thats unknow territory
if it POSTS (50% chance), then it will boot in auto config mode, XMP probably wont work as you get two different XMP profiles
so manually inserting XMP values from higher latency sticks should probably work
if it doesnt POST
insert you current faster sticks in B1+B2 slots and new slower sticks in A1+A2 (as by default old sticks were in A2+B2 and new in A1+B1)

 

[ssilverm]

"I'm guessing this isn't going to be a major issue "

Boy, I wish I'd never written that!

Thanks for all the advice.

Steve

 

[mamasan2000]

50% that it will work
CPU itself should run 3200MHz with 4 sticks
as for mainboard, thats unknow territory
if it POSTS (50% chance), then it will boot in auto config mode, XMP probably wont work as you get two different XMP profiles
so manually inserting XMP values from higher latency sticks should probably work
if it doesnt POST
insert you current faster sticks in B1+B2 slots and new slower sticks in A1+A2 (as by default old sticks were in A2+B2 and new in A1+B1)

Adding to this

To Lafong

I had 2 kits of Corsair Vengeance 3000 Mhz. One set was Hynix AFR, the other Samsung D or C-die, the one that doesn't like voltage over 1.35v. 2800 Mhz was easy to get to run. I just selected the speed, dropped all primaries by one and it worked. Probably why I didn't make a real effort to get it to work at 3000 Mhz. Difference is so small. But eventually, 3-6 months later, after tinkering with RAM now and then, I got it to run at 3000 Mhz. It's the only time I have used mixed kits IIRC. In a way I was lucky. I tested the Hynix AFR on my new system. it didn't clock much higher, think I couldn't get past 3333 Mhz. While the 2nd kit I got, years later, the Samsung kit, I had that running at 3800 Mhz. Of course with looser timings and restricted to 1.35v. So the new kit was better. I had already played/overclocked with the old kit for like a year so I knew what it could and couldn't do.

You have to find a combination of settings that works for both kits, at all times. Just 1 timing that is off by 1 tick and it's not going to work. It's tedious work. Extremely so. Changing one setting and testing RAM stability. The more RAM you have, the longer the testing takes too.
I did it for fun and for the learning experience. If you are not into that and tinkering hours per day for extended periods of time...

Save yourself the trouble. Get a matching set. A kit that comes with the capacity and speed you need.