[dwallace]

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.

Thanks!!!

 

[dwallace]

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

 

[dwallace]

I have just decided to leave it clocked at 1866Mhz 9-9-9-24 2T timings and call it good. Ran prime95 for hours with these settings and no errors. I really appreciated the help on this

 

[dwallace]

Some interesting info: My father built an identical system to mine recently. He cannot run his 2400 ram at 2400 either. It lags windows on boot up and eventually BSOD. Bios are not correct also.....at 1600 it wanted to run them 1.7v and incorrect timings. Exact same prob I experienced with 2 different (QVL) ram. I have been in contact with an Asus rep and have supplied him with the 2 mb serial numbers for testing. Though, I have a feeling after reading the post here and off a couple other forums it is the i7-4790K IMC.

I didn't want to have 2400 mem i couldn't fully use so I actually ended up RMA'ing it and went with some 1600 Adata. My pc is running like it should have from the beginning. So freaking fast

It oc'ed to 4.9Ghz easy but decided to just run it on turbo 4.4Ghz. Temps are nice also....Using an Enermax Liqmax 120s (push-pull) my temps idle around 32. Fully loaded gaming for a couple hours it never gets above 59c, So I'm pretty happy

.

I wish that I would have just bought 1600 ram from the beginning

Would have saved me a lot of headaches