F3-14900CL8Q-16GBZM maximum timings @800MHz

[nine_seven]

Hello again,

it's been a while since I last wrote in this Forum, but now I am back with a new build and a new problem. ;-)

I've recently bought a Gigabyte GA-970A-UD3P Mainboard and an AMD FX-8350 CPU together with the above mentioned RAM modules.
Now there is an issue with this board not being able to run DDR3-1866 in all 4 DIMM Slots, but the manufacturer states this on his website, so there is nothing to do about that.

However, since I cannot run my RAM at 933MHz, like I was hoping to, I thought I might be able to run the RAM at sharper timings and 800MHz and have been trying to do so very successfully. My current timings are 8-9-9-24 CL1.

Now my question is, if there are timings like the XMP for this RAM @800MHz that were tested by G.Skill, so that I do not have to manually try to find out the limits of the RAM and to not void the warranty on the RAM.

I've already used AIDA64 to find out about the timings in XMP, but there are just standard timings given for 800MHz.

Thanks in advance
nine_seven

[Priller]

Try bumping the CPU/NB to 1.25V and try for 1866 speed.

[emissary42]

I don't think there are officially tested timings on lower speeds other than what the SPD provides. However based upon what type of IC is used on this kit, i'd just try 7-8-8-20. You might need to raise Vdimm a bit, but it should be doable without going all out.

Regarding DDR3-1866 Priller already nailed it. Additionally raising the tRFC one step might also help sometimes.

[nine_seven]

Alright, thanks a lot. I'll try it out when I have a minute and report back.

[nine_seven]

Well, I tried everything you mentioned above, but the DDR3-1866 speed is still out of my reach. I even tried to set the MB/NB Voltage to 1.2 instead of 1.1V while having the CPU/NB @ 1.25V, but my system just would not boot.

I guess that's what Gigabyte meant by stating this in their memory compatibility list:
Note: Only one DIMM per channel is supported for DDR3-1866MHz and higher speed as using an AM3+ CPU.

When I saw Priller's post I was hoping that this was an issue of the CPU but it's certainly not!

Luckily, the timings emissary42 posted are working and even with CR1!

There is but one thing left now: How do I know if my system will perform stable at those timings? Are there any tests to find that out or will only time show?

[Priller]

You dont need to raise the MB/NB voltage to 1.2. Lower it back to 1.1

Try removing 2 sticks of ram and see if it will run at 1866. Most likely it will as 4 sticks are hard on the IMC.

If you really want that 1866 speed with the stock timings and 4 sticks.

Set the CPU/NB to 1.25V
Set ram voltage to 1.525V
Set the ram multiplier to give you 1600mhz then start walking the FSB up until you get to 1866.

I find it easier to get higher memory speeds with the CPU at a bit of an overclock when a particular CPU has a weak IMC. You will need to get to 233 on the FSB to get to 1864mhz on the ram but walk it up slowly as it will increase core speed and you may need to bump the Vcore up.

Also CL8 1866 is faster then 1600CL7.

[nine_seven]

Thanks for the continued help. I am sure, that the RAM would clock @1866 if I left 2 sticks out, but that's a total no go for me, since I do want to use 16GB.

Well, I will give the proposition about walking up the FSB a go but I don't expect too much, because this board is not meant for overclocking.

Anyways, I was gaming earlier today and the 7-8-8-20 CR1 timings seem absolutely stable to me, so if I can't get the RAM to 1866 I'll just stick to that. Sure, this would mean less performance, but better that than frequent blue screens because of unstable overclocking.

I'll let you hear how it worked out later tonight.

[nine_seven]

Alright... seems like this just turned into an overclocking thread...

After taking the timings down to 8-9-9-24 CR2 and increasing the CPU/NB voltage to 1.2V I was able to get the FSB up to 225MHz without any problems so far.

This is definitely not the end of the line since I haven't raised any other voltages yet but for now this makes me feel slightly optimistic.

I also haven't tried the current setup with Prime95 to make sure about stability or heat issues and so on but I will see to that later.

Thanks again for your help and I will keep you updated about the going of the overclock.

[Priller]

So that puts you at 1800mhz on the ram which is good and you're getting closer.

Just keep playing with it and you may have to bump the vcore and/or the CPU/NB just alittle bit to get the last bit out of it.

[GSKILL TECH]

Rather than raising CPU FSB, you should try using the memory multiplier only because if you raise CPU FSB, it overclocks everything else and adds stress all around.

Should be able to get DDR3-1866 8-9-9-24 or DDR3-1600 7-8-8-24

good luck!

[nine_seven]

@GSkill Tech:
If getting DDR3-1866 was as easy as raising the memory multiplier, I would have gladly done that.
But I would be very interested as to what components exactly might be put under additional stress, if I only raise some clock settings and the CPU/NB from 1.15V to 1.2V.
As far as I know, this hardly makes any temperature difference and cooling is definitely not a problem on my PC. I also lowered the CPU multiplier and HT/NB clocks back to a normal level once I had the 225MHz FSB. While gaming yesterday I found no problems with those settings but I know that gaming cannot put the CPU at real stress.

@Priller:
I will. I think that 233MHz FSB might even be possible after what I've seen now. Of course I will keep the CPU and HT/NB clocks at a normal level so I don't get any trouble with that.

[Priller]

I have found as long as you keep the HT link and NB freq below 2800mhz you shouldn't have any problems with raising the FSB and adding little touches of CPU/NB and CPU Vcore voltage. Some CPUs and motherboards will let you go to 3000mhz without issues but your mileage may vary of course. When you start pushing the speeds is when you might need to start looking at HT link voltage etc but I wouldn't worry about that until you start looking into ridiculous HT/NB speeds.

[nine_seven]

Alright, I think I got it figured out:
The reason why my system would not boot with the RAM set to XMP is not the frequency but the ADVANCED TIMINGS.

I just encountered a boot failure after editing the advanced timings of the RAM while leaving everything else untouched.
After that I tried to leave the system at stock frequencies while increasing memory frequency to 933MHz and manually setting the timings to what they were yesterday while overclocking.
And guess what: my system booted!

Interestingly though these advanced timings are sometimes faster and sometimes slower than those of the XMP. Maybe some of those guys who are more into memory timings could explain why they are working?

Here is what I set:
CL 8
RCD 9
RP 9
RAS 24

RC 39
RFC 160 (due to MB)
CR 2
RRD 5
WR 12
WTR 6
RTP 6
FAW 24
WCL 8

This is what XMP says:
CL 8
RCD 9
RP 9
RAS 24

RC 33
RFC 150
CR 2
RRD 6
WR 15
WTR 8
RTP 8
FAW 26
WCL 7

[emissary42]

RC 33
RFC 160
CR 2
RRD 6
WR 15
WTR 8
RTP 8
FAW 26
WCL 7 (8)

is what EOCP should set them with the XMP enabled (AMD motherboards have no native support for Intel Extreme Memory Profiles). If it tries to set RFC=110, the next smaller value for RFC, then thats probably why it fails with AUTO subs.

[nine_seven]

I finally figured out, which timing value caused the problems:

WCL 7
If I set this one value to 8, the system boots up fine.
I also set all the other timings to what is specified in XMP because I don't want to run the RAM out of spec.
System is running stable so far. Unbelievable that it really was only this one tiny value that blew the whole thing!

Thank you all again for your help. I think I would have just given up and stayed with DDR3-1600 speed without you.

nine_seven