X5650 CPU OC Instability under 980Ti

[funky_llama1]

Hi all,

I'm a long term lurker and don't post here often. My account used to have a few more posts but I lost my old account due to an email address change a while back. I've been following the 980 Ti owners thread and finally bit the bullet last week. Anyway I hope you might hear my cry for help to solve this.

I became the proud owner of a Gigabyte G1 Gaming GTX 980 Ti on Friday (from OCUK of course) First off heres the obligatory pic of this beast dominating my case.

Spoiler

Initially everything went well. I installed the card and booted up without any issues. I then proceeded to install my graphics drivers and update Afterburner. At that point I rebooted and got no post.

I rebooted my system and got an unstable overclock warning so proceeded to boot at stocks. I fired up GTA V and had a quick play session followed by an hour or so of Witcher 3. I must say that the card performs great. I went from around 45-50fps in Witcher 3 on very high 1440p settings with my GTX970 to around 75-80 which is quite impressive. On my Acer XB270HU its glorious. Watching the GPU usage it was varying between 99% and 93% in places so I feel like it might be hitting a sight bottleneck with my CPU at sock clocks.

Next I tried applying my CPU overclock settings from my "stable 4.2" profile in the bios. This is where I have had my X5650 at for the last 6 months without a single failure. Again I got no post and had to do a bios reset to get it to boot at stocks again.

Thinking WTH I backed it off a good bit to 3.5Ghz. This time my system posted and I got as far as the Win 8 loading screen but then I got a blue screen and automatic restart. This was again a previously "stable" profile saved from several months ago. I realised this profile had a lot more headroom volts wise with 1.275 vcore and 1.275 QPI. I upped this to the previous level I used to achieve 4.2Ghz@ 1.31 vcore and 1.375 QPI. This posted again and I got as far as Windows 8 loading. Then the real trouble started with Windows. I got stuck in a loop of the Windows repair tool running and telling me it was unable to start followed by a reboot and then the repair tool doing the same process again. I went back to stocks but no joy.

I had a BBQ to attend last night so had to leave it, very frustrated. I came back today and did several repairs from a rescue disk to no avail. To cut a long story short I eventually broke it out of this cycle by booting into Safe mode and then doing a normal reboot Thanks Windows 8.

After this episode I am wary of doing any more overclocks to my CPU for now. I am keen to get my overclock back though as feel like my shiny new GPU isn't operating to its full potential. I cant for the life of me figure why only changing my GPU has completely destabilised what was a rock solid overclock for several months. I would like to understand what has changed before I plow on and start my overclock from scratch. My thoughts are maybe this is a voltage issue. I have a Corsair 1000W PSU so I'm pretty sure thats more than capable. The last thing I want to do is damage a rather expensive graphics card.

Gigabyte EX-58 UD5 F13j bios
Xeon X5650
Teamgroup DDR3 PC3-17000C9 2133MHz 12GB
Corsair HX1000W
Custom Water (CPU Only at the moment)
G1 Gaming GTX 980Ti
Asus Xonar DX Audio
Crucial MX100 500Gb
2x 1tb Seagate

Previous stable OC settings @ 4.2Ghz
http://imgur.com/a/GTxRG

I've done 3 runs of IBT at maximum stress and my CPU is alive and kicking at stock speeds so no permanent harm done.

I will also mention that this isn't a long term solution and I know my system is well overdue an upgrade. I like many others am waiting on Skylake, then I'll be jumping that band wagon if its any good or will be reconsidering a Haswell-E setup.

I'm not new to overclocking by any means but I only tend to dive into this sort of thing when I get a new piece of kit and then I leave it alone. Theres probably something I have forgotten or am missing so I would appreciate some more experienced folks opinions.

 

[funky_llama1]

I had another go at overclocking last weekend and was able to reach 3.96Ghz stable in windows (22x180). It passed 3 runs of IBT max stress, handbrake and some Prime95 with 1.275v Vcore and 1.285 QPI volts. I am now getting cold boot issues though. It will fail to post initially and wont boot until I power of the power supply at the back and then it will post at stocks and say there has been an overclocking error. I've tried upping the Vcore and QPI slightly and had a play around with the PLL and IOH which made no difference.

Its so weird how it was stable before the Ti. Does it sound like a power supply issue to anyone? Again its a decent quality 1KW and so I'm reluctant to replace it on a whim. I am a bit worried now though. With a new build on the horizon I'm half tempted to replace it, its a few years old now and has served me well.

 

[funky_llama1]

I tried upping the volts to 1.35v / 1.35 vtt which is as high as I dared go and still got failed posts. Oddly enough I knocked off HT and the last two days its posted from cold. I havent really noticed a performance hit in Witcher 3 so am happy to leave it at that for now.

I did have another issue this evening when I powered the system on I got as far a verifying DMI pool and then got 'Recovering Lost DRAM size'. The system rebooted itself and then it was fine. All 12gb showing in windows. Starting to think maybe its by ram though. Will put it through some memtest this weekend. I have a spare stick I can throw in if one of the modules is faulty as I bought a quad channel set.

Roll on the 5th