[SOLVED] Slower ram with 4 modules?

Nov 23, 2018
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I`ve just installed another ram module, was running 24gb oc to 3000 MHz, and after installing the 4th, performance took a big hit.
With 3x8gb i was able to get 2650 on Performance Test 9.0. After upgrading to 4x8gb i only get about 2200. Is that normal?
All the modules are Corsair Vegeance LPX, 3 rated at 2400MHZ and the newer one is 2666.
On the bios ive set them at 17-17-16-33 (wich was running fine with 3 modules) and no instability issues at the moment.

Changing the subject a little, is there any guide for ddr4 secundary timmings tunning?
 

Darkbreeze

Titan
Moderator
This is what I've somewhat loosely adapted my methodology from. Mostly, it's good. As mentioned in the guide itself you'll have to do some experimentation as every configuration is somewhat different.

https://www.overclock.net/forum/26096937-post1.html

I would go back and make sure that the timings are still where you set them. Often, when you add a stick, it may auto configure to different settings if it detected instability at the current settings because of a new stick.

Also, make sure that it didn't default them ALL to 2133mhz.

Of utmost importance, is testing stability. Memory corruption IS NOT A JOKE. It is SERIOUS. You WILL corrupt ALL data that gets written or saved if there is not full stability.

My testing procedures are outlined here:

 
Nov 23, 2018
16
0
10
0
This is what I've somewhat loosely adapted my methodology from. Mostly, it's good. As mentioned in the guide itself you'll have to do some experimentation as every configuration is somewhat different.

https://www.overclock.net/forum/26096937-post1.html

I would go back and make sure that the timings are still where you set them. Often, when you add a stick, it may auto configure to different settings if it detected instability at the current settings because of a new stick.

Also, make sure that it didn't default them ALL to 2133mhz.

Of utmost importance, is testing stability. Memory corruption IS NOT A JOKE. It is SERIOUS. You WILL corrupt ALL data that gets written or saved if there is not full stability.

My testing procedures are outlined here:

Ive actually cleared the cmos and set everything manually, it was at 2133 before that. Cpu z and memtest 64 are reporting 3000mhz on all 4
 

Darkbreeze

Titan
Moderator
Well, unfortunately it's always a crapshoot when you mix memory, especially once you are beyond the speed and timings that are consistent with the JEDEC defaults/standards. Even the same model, but not all in one kit, can be problematic. I'm assuming you have two modules from one kit, another added module that was not part of that kit and a fourth module that isn't even remotely close to the other two in terms of specifications and also onboard components used. I'm actually sort of surprised that it even works.

https://forums.tomshardware.com/threads/amd-ram-compatibility.3210050/post-19785792

Or even allow a company to replace only one faulty stick out of a set.

https://forums.tomshardware.com/threads/g-skill-trident-z-f4-4133-19-cas-2x8gb-xmp-profile-problems.3462507/#post-20973904
 
Nov 23, 2018
16
0
10
0
Well, unfortunately it's always a crapshoot when you mix memory, especially once you are beyond the speed and timings that are consistent with the JEDEC defaults/standards. Even the same model, but not all in one kit, can be problematic. I'm assuming you have two modules from one kit, another added module that was not part of that kit and a fourth module that isn't even remotely close to the other two in terms of specifications and also onboard components used. I'm actually sort of surprised that it even works.

https://forums.tomshardware.com/threads/amd-ram-compatibility.3210050/post-19785792

Or even allow a company to replace only one faulty stick out of a set.

https://forums.tomshardware.com/threads/g-skill-trident-z-f4-4133-19-cas-2x8gb-xmp-profile-problems.3462507/#post-20973904
The first 2 modules were bought toghether, but not from a kit, the third i traded (same model) for a ddr3 i had, the fourth arrived today, same product line (LPX Vengeance) and timings, only 2666 mhz. I only bought this because i thought that i needed dual channel on both channels or it would damage performance, if that make any sense. Weird thing is that with the one i got from the trade, used without even knowing it was any good, worked like a charm and accepted the oc very well.

Looking at the Performance test results, the memory write was the most affected, maybe there is some setting at the bios that i didn't configure properly? It shouldn't perform worse than a 2133hz on dual channel since it is at 3000 (even with compatibility issues).
 

Darkbreeze

Titan
Moderator
I'd set ALL of the memory to 2400mhz, manually, for the same settings as what the 2400mhz sticks run at with their XMP profile enabled. Leave the secondary timings on auto.

Run four passes of Memtest 86. If it passes all four runs of all 11 tests without ANY errors, then set the memory speed to 2666mhz and use the timings from those sticks. Test again.

Then leave it or begin tightening timings. There is no way possible you can get those 2400mhz sticks x3 (One of which is not even a matched stick) PLUS a 2666mhz stick with a different composition in terms of ICs and specifications, to all run at a 3000mhz OC and be stable. If you can set all four sticks at 3000mhz without a single error in four passes of Memtest AND this test below, I'd be completely amazed, and I'm doubtful to the point of practically being certain that it's not going to happen. Too many variables between sticks and too big of an increase in frequency. I just don't see that happening. MAYYYYBEE, 2800mhz, but you'd need to validate at these lower speeds and timings first.

And if you can't pass four passes of Memtest 86, all 11 tests, plus the custom Prime test below, then it's an unstable OC anyhow and doesn't matter because you're going to be losing all your files in about two months anyhow, if not sooner.



Final testing with Prime95

It is highly advisable that you do a final test using Prime95 version 26.6 (And ONLY version 26.6 except as noted below) choosing the Custom test. You can also use the Blend mode option but after a fair amount of personal testing, asking questions from some long time members with engineering level degrees that have forgotten more about memory architectures than you or I will ever know, and gathering opinions from a wide array of memory enthusiasts around the web, I'm pretty confident that the custom option is a lot more likely to find errors with the memory configuration, and faster, if there are any to be found.

Please note as this is rather important, if you prefer, or have problems running version 26.6 because you have a newer platform that doesn't want to play nice with version 26.6, you can use the latest version of Prime95 with the Custom test selected but you will need to make the following change.

If you wish to use a newer version than 26.6 make the following edit to the "local.txt" file located in the Prime95 folder.

Find the line value that specifies CpuSupportsAVX=1, and change it to CpuSupportsAVX=0

Then click File-->Save, and then close the document.

Now open Prime95.

Click on "Custom". Input a value of 512k in the minimum FFT size field. Leave the maximum FFT size field at 4096k. In the "Memory to use" field you should take a look at your current memory allocation in either HWinfo or system resource monitor. Whatever "free" memory is available, input approximately 75% of that amount. So if you currently have 16GB of installed memory, and approximately 3GB are in use or reserved leaving somewhere in the neighborhood of 13GB free, then enter something close to 75% of that amount.

So if you have 13GB free, or something reasonably close to that, then 75% of THAT would be 9.75GB, which, when multiplies times 1024 will roughly equal about 9984MB. You can average things out by simply selecting the closest multiple of 1024 to that amount just to keep it simple, so we'll say 10 x 1024= 10240mb and enter that amount in the field for "Memory to use (MB)". We are still well within the 13GB of unused memory BUT we have left enough memory unused so that if Windows decides to load some other process or background program, or an already loaded one suddenly needs more, we won't run into a situation where the system errors out due to lack of memory because we've dedicated it all to testing.

I've experienced false errors and system freezes during this test from over allocating memory, so stick to the method above and you should be ok.


Moving right along, do not change the time to run each FFT size.Leave that set to 15 minutes.

Click run and run the Custom test for 8 hours. If it passed Memtest86 and it passes 8 hours of the Custom test, the memory is 100% stable, or as close to it as you are ever likely to get but a lot of experts in the area of memory configuration suggest that running the extended Windows memory diagnostic test is also a pretty good idea too.

If you get errors, (and you will want to run HWinfo alongside Prime95 so you can periodically monitor each thread as Prime will not stop running just because one worker drops out, so you need to watch HWinfo to see if there are any threads not showing 100% usage which means one of the workers errored and was dropped) then you need to either change the timings, change the DRAM voltage or change the DRAM termination voltage, which should be approximately half of the full DRAM voltage.

There are also other bios settings that can affect the memory configuration AND stability, such as the VCCIO and system agent voltages, so if you have problems with stability at higher clock speeds you might want to look at increasing those slightly. Usually, for Intel at least, something in the neighborhood of 1.1v on both those is pretty safe. There are a substantial number of guides out there covering those two settings, but most of them are found within CPU overclocking guides so look there in guides relevant to your platform.

As a further measure of assurance that your WHOLE configuration is stable, you can download and run Realbench for 8 hours. If the system freezes or fails when running Realbench with your full memory amount set, try running it again but select only half your amount of installed memory.
 
Nov 23, 2018
16
0
10
0
I'd set ALL of the memory to 2400mhz, manually, for the same settings as what the 2400mhz sticks run at with their XMP profile enabled. Leave the secondary timings on auto.

Run four passes of Memtest 86. If it passes all four runs of all 11 tests without ANY errors, then set the memory speed to 2666mhz and use the timings from those sticks. Test again.

Then leave it or begin tightening timings. There is no way possible you can get those 2400mhz sticks x3 (One of which is not even a matched stick) PLUS a 2666mhz stick with a different composition in terms of ICs and specifications, to all run at a 3000mhz OC and be stable. If you can set all four sticks at 3000mhz without a single error in four passes of Memtest AND this test below, I'd be completely amazed, and I'm doubtful to the point of practically being certain that it's not going to happen. Too many variables between sticks and too big of an increase in frequency. I just don't see that happening. MAYYYYBEE, 2800mhz, but you'd need to validate at these lower speeds and timings first.

And if you can't pass four passes of Memtest 86, all 11 tests, plus the custom Prime test below, then it's an unstable OC anyhow and doesn't matter because you're going to be losing all your files in about two months anyhow, if not sooner.



Final testing with Prime95

It is highly advisable that you do a final test using Prime95 version 26.6 (And ONLY version 26.6 except as noted below) choosing the Custom test. You can also use the Blend mode option but after a fair amount of personal testing, asking questions from some long time members with engineering level degrees that have forgotten more about memory architectures than you or I will ever know, and gathering opinions from a wide array of memory enthusiasts around the web, I'm pretty confident that the custom option is a lot more likely to find errors with the memory configuration, and faster, if there are any to be found.

Please note as this is rather important, if you prefer, or have problems running version 26.6 because you have a newer platform that doesn't want to play nice with version 26.6, you can use the latest version of Prime95 with the Custom test selected but you will need to make the following change.

If you wish to use a newer version than 26.6 make the following edit to the "local.txt" file located in the Prime95 folder.

Find the line value that specifies CpuSupportsAVX=1, and change it to CpuSupportsAVX=0

Then click File-->Save, and then close the document.

Now open Prime95.

Click on "Custom". Input a value of 512k in the minimum FFT size field. Leave the maximum FFT size field at 4096k. In the "Memory to use" field you should take a look at your current memory allocation in either HWinfo or system resource monitor. Whatever "free" memory is available, input approximately 75% of that amount. So if you currently have 16GB of installed memory, and approximately 3GB are in use or reserved leaving somewhere in the neighborhood of 13GB free, then enter something close to 75% of that amount.

So if you have 13GB free, or something reasonably close to that, then 75% of THAT would be 9.75GB, which, when multiplies times 1024 will roughly equal about 9984MB. You can average things out by simply selecting the closest multiple of 1024 to that amount just to keep it simple, so we'll say 10 x 1024= 10240mb and enter that amount in the field for "Memory to use (MB)". We are still well within the 13GB of unused memory BUT we have left enough memory unused so that if Windows decides to load some other process or background program, or an already loaded one suddenly needs more, we won't run into a situation where the system errors out due to lack of memory because we've dedicated it all to testing.

I've experienced false errors and system freezes during this test from over allocating memory, so stick to the method above and you should be ok.


Moving right along, do not change the time to run each FFT size.Leave that set to 15 minutes.

Click run and run the Custom test for 8 hours. If it passed Memtest86 and it passes 8 hours of the Custom test, the memory is 100% stable, or as close to it as you are ever likely to get but a lot of experts in the area of memory configuration suggest that running the extended Windows memory diagnostic test is also a pretty good idea too.

If you get errors, (and you will want to run HWinfo alongside Prime95 so you can periodically monitor each thread as Prime will not stop running just because one worker drops out, so you need to watch HWinfo to see if there are any threads not showing 100% usage which means one of the workers errored and was dropped) then you need to either change the timings, change the DRAM voltage or change the DRAM termination voltage, which should be approximately half of the full DRAM voltage.

There are also other bios settings that can affect the memory configuration AND stability, such as the VCCIO and system agent voltages, so if you have problems with stability at higher clock speeds you might want to look at increasing those slightly. Usually, for Intel at least, something in the neighborhood of 1.1v on both those is pretty safe. There are a substantial number of guides out there covering those two settings, but most of them are found within CPU overclocking guides so look there in guides relevant to your platform.

As a further measure of assurance that your WHOLE configuration is stable, you can download and run Realbench for 8 hours. If the system freezes or fails when running Realbench with your full memory amount set, try running it again but select only half your amount of installed memory.
Something very funny happened: Everything at 2400 mhz stock gets 3295 compared to 2197 on Performance test. Ill just find the sweetspot and forget about 3000. Thanks for the help @Darkbreeze
 

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