Help with i7 4790k + DDR3 2400 errors

[willowin]

I recently built a new pc and am having a lot of problems getting my ram to run at 2400Mhz. When its set to 2400 and any cpu clock speed (even default) It fails Prime95 within seconds and causes BSOD when I try to play a game like BF3-4. At 1866Mhz + 4790K oc to 4.7Ghz it passes Prime95-Memtest86 no errors and is rock solid playing games. Here is what I'm running :

Asus Z97-A
i7 4790K
Corsair Dominator Platinum DDR3 2400 (2x8gb) 16Gb

I have used the XMP in combination with default stock cpu clocks with no success. I have set it manually, no luck. The DRAM voltage is good at 1.65 auto shows it as 1.68v. The timings are correct for 2400 speed. I actually RMA'd the first ram I got thinking it was bad mem and ordered the Corsair sticks. So I know the ram is good. Am I missing something, could my board be faulty or is that normal for 2400Mhz ram not able to run full speed on this board? Any help would be greatly appreciated.

 

[Tradesman1]

With your CPU OC in place, or at least a minimum of 4.1, enable XMP, selct profile 1 and then raise the CPUVTT or VTTDDR to about 1.13 (it's your MC (memory controller) voltage)

 

[willowin]

With your CPU OC in place, or at least a minimum of 4.1, enable XMP, selct profile 1 and then raise the CPUVTT or VTTDDR to about 1.13 (it's your MC (memory controller) voltage)

Thank you for your quick reply.

The VTTDDR was set to auto and showing a voltage of 0.825 so I tried to raise it to 1.13v but even with extreme oc enabled it would only let me raise it to 1.0v. I went ahead and tried stress test and it immediately failed. Also, 2133 failed at 1.0v so I set it back to auto and DRAM 1866. Is there a way on the Asus Z97-A to increase the VTTDDR beyond 1.0V? Should I RMA my cpu? Its less than 30days old and still eligible for replacement from Newegg.

Thank you

 

[Tradesman1]

Might try at 0.95 and increase CPU voltage + 0.05

 

[willowin]

Might try at 0.95 and increase CPU voltage + 0.05

Thanks once again for your prompt reply. I have decided just to run the ram at 1866Mhz with 9-9-9-24 2T. It passed prime95 for several hours with no errors at those settings so I'm calling it good.

Your help was really appreciated

 

[Tradesman1]

No worries, have fun!

 

[Sherwin Ianne Caliva]

Anyone knows what RAM speed is i7 4790k stable with? I am seeing here that 2400 is not stable on 4790k whereas in 4770k it is a no fuss.

 

[Tradesman1]

2400 should be fine (may take a small CPU OC), may have problems in their setup depending on mobo and BIOS

 

[willowin]

I'm not sure what was going on with my i7 4790k + 2400. The only stable setting was 1866 on 2 different (QVL) memory. Anything higher my games would freeze and BSOD and also fail prime95, memset86. 1866 and lower it runs extremely stable and fast. I am RMA'ing the 16Gb Corsair Dominator Platinum 2400 and have ordered some less expensive 16Gb Adata 1600 (QVL). Also, I am working with an Asus rep to make sure it's not a MB issue.

 

[Tradesman1]

Sounds like mobo, in particular the BIOS,

 

[willowin]

Sounds like mobo, in particular the BIOS,

Got reply from the Asus rep and he seems to think it could be a bent cpu socket pin. But I don't think so. I set the cpu perfect the first try and haven't noticed any issues other than the 2400 ram. Do you think that his assumption about the pins could be correct? I'm really not wanting to pull it out to look. Wouldn't the CPU have failed stress test?

Thank you in advance for your reply.

 

[Tradesman1]

Possibly it's the CPU cooler is too tight in a corner or on one side, that can throw he CPU from the level state it should be sitting in and affect the pin contact, might loosen cooler then just snug it back down, not overly tight and try (and yes, could be a bent pin, I try and save that for last ditch as you have to remove CPU, new TC all that good stuff

 

[willowin]

I tightened down the cooler pretty snug. I'll give it a look.

Thank you

 

[Tradesman1]

Let me know

 

[willowin]

Let me know

I reset the cpu cooler, it was really tight. Then I installed some new 1600 xmp ram. My pc is running so smooth now and passed stress for 5 hours which it did before with my 2400 ram set at 1866.

Here is some interesting info:

My dad just build an identical system to mine. Z97-a, i7 4790K and 2400 QVL 2400 ram. His memory at 1600 on auto sets the voltage at almost 1.7v and wrong timings. But when set manually 1.5v and 9-9-9-24 it runs awesome. When set to xmp 2400 1.68v 11-13-13-35 it causes windows to stall on loadup and stutters. Seems a little too coincidental to me. Maybe the board needs a bios update....I'm going to let the rep from Asus know my findings. Maybe they will test the board with the same setup.

Thanks

 

[JohhnyQ85]

hellooooo there! just reviving this old thread. Im about to get 2 sticks of 2133 CL11 and was wondering if i will need to OC the i7 4790k or just enabling the xmp will do the trick.


thanks everyone!

 

[JohhnyQ85]

also, the voltage for 2133 is 1.6

 

[Tradesman1]

Give it a try, it will depend on your individual 4790K, many will run 2133 while at stock, some may need a slight CPU OC

 

[JohhnyQ85]

Give it a try, it will depend on your individual 4790K, many will run 2133 while at stock, some may need a slight CPU OC

Mmmm, thats not very encouraging. Does it really depend on the cpu??? Silicon maybe? Lol

What would indicate i need a cpu oc?

 

[Tradesman1]

Primarily it's the MC (memory controller) in the CPU, and yes it's silicon lottery have seen 4790Ks that easily run 2400 while at stock and others that labor with 1866....if you try and no joy, we can try a little extra voltage to the MC which often does the trick, can also play with the DRAM timings, otherwise a small CPU OC does it

 

[Sergio_17]

been having the same issue with my 4790k and the 2400 1.65v ram. it doesnt run stable at 1.65v so i turned the settings down a lil i was able to run the ram at 2000 and 1.5v no crashes at all..... get a decent 2400 1.5v ram or just turn it down a lil.. good luck