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View Full Version : Need help settling on RAM speed and timings



MikeS3000
03-05-2017, 12:25 AM
So I have some 8gb x 2 Corsair Vengeance LPX RAM that is rated at 3200 Mhz CAS 16 @1.35. I have overclocked just about everything on my Kaby Lake build except for the RAM so I thought what the heck, let's see what we can do. I bumped voltage to 1.375 and was surprised at what I unlocked. With lots of Memtest86 and Memtest HCI testing I tried to find the best speed and tightest timings. Here is what is stable, which is better and why?

1. 3600 Mhz 16-18-18-36 2T
2. 3200 Mhz 14-16-16-36 2T

I don't think I want to push voltage further as I'm pretty happy with these results. The only benchmark I have been using is AIDA64's Cache and Memory Benchmark and the 3600 Mhz wins in just about every category. If we're talking real world performance which is best?

Nate152
03-05-2017, 12:46 AM
Hi Mike

You can take the voltage to 1.50v that's pretty much the safe max for ddr4.

But in answer to your question you could run this little benchmark and see which is faster. I bet they'll be pretty close I voted 3600MHz for the frequency.

http://www.maxxpi.net/pages/downloads/maxxmemsup2---preview.php

Here is my score. :)

Kingston HyperX Predator 16GB 3000MHz 15-15-15-35-2T

62898

MikeS3000
03-05-2017, 03:42 PM
So now I need some guidance regarding one annoying issue. My memory at 3600 Mhz passed Metest HCI @1000% coverage no errors, and memtest86 4 passes no errors. When I go to reboot from Windows, the machine fails to get past the POST and just hangs. A manual power off and then back on gives me the usual message that Safe Boot has been enabled due to a failure to post. I go into the BIOS and save and exit and Windows boots fine. Why is my motherboard having trouble on reboots?

Edit: ok so that's weird. The issue occurs randomly. After a fresh boot and running windows for a few minutes I rebooted and the system did not hang. The failure to post seems to occur after being up and running for several hours.

manjews
03-08-2017, 04:25 PM
Hi Mike

You can take the voltage to 1.50v that's pretty much the safe max for ddr4.

But in answer to your question you could run this little benchmark and see which is faster. I bet they'll be pretty close I voted 3600MHz for the frequency.

http://www.maxxpi.net/pages/downloads/maxxmemsup2---preview.php

Here is my score. :)

Kingston HyperX Predator 16GB 3000MHz 15-15-15-35-2T

62898


That is interesting. I am running 16GB of G.skill trident z at 3600mhz 16-16-16-36-2t with a 7700k and my scores are significantly lower than yours. How many dimms are you running?

manjews
03-08-2017, 04:37 PM
So now I need some guidance regarding one annoying issue. My memory at 3600 Mhz passed Metest HCI @1000% coverage no errors, and memtest86 4 passes no errors. When I go to reboot from Windows, the machine fails to get past the POST and just hangs. A manual power off and then back on gives me the usual message that Safe Boot has been enabled due to a failure to post. I go into the BIOS and save and exit and Windows boots fine. Why is my motherboard having trouble on reboots?

Edit: ok so that's weird. The issue occurs randomly. After a fresh boot and running windows for a few minutes I rebooted and the system did not hang. The failure to post seems to occur after being up and running for several hours.

I was actually having the same issue when trying to run my Tridentz at the rated 3866mhz. Turns out the issue was that the VCCIO & VCCSA voltages. These voltages can be very tricky to get correct. If not set properly they can cause the system to fail to POST occasionally, while being perfectly stable once booted.

I would see what those voltages are set to and try bumping them slightly. Bumping the voltage too much can actually increase instability so be careful with your adjustments. This guide has more information:
http://edgeup.asus.com/2017/01/31/kaby-lake-overclocking-guide/3/

I spent about a week messing around with those voltages on mine and finally just gave up. I remote into my machine often and I need my computer to boot consistently if rebooted remotely. I ended up going from 3866 18-19-19-39 to 3600 16-16-16-36 and I have not had any issues since.

Nate152
03-08-2017, 04:52 PM
That is interesting. I am running 16GB of G.skill trident z at 3600mhz 16-16-16-36-2t with a 7700k and my scores are significantly lower than yours. How many dimms are you running?

I'm running 2 dimms 2 x 8GB.