Hi Guys,
I joined the X99 club over Christmas and over the last few days have finally had a chance to spend some time tuning it up.
Spec is as follows:
i7 5820k
Silver Arrow IB-E
Asus X99 Deluxe
Gskill 2666MHz C15
7990 + 7970 (Trifire)
Superflower Leadex Platinum 1000W
Corsair 750D
Win 8.1 Pro
The 7970 was from my previous machine and the 7990 was bought from the MM for some fun. I also picked up the Deluxe in the MM as this would normally be out of my price range. Some might ask why i didn't go for the 5930k given there are 3 GPUs but I figure if x16 is good enough for dual 7970s (i.e. a 7990) then x8 is good enough for one. I just couldn't justify £170 extra for 12 PCI-E lanes.
Background
I have little previous OC experience. My previous system was based on an i5 750 bought on launch day in Oct '09. My goal was to play BF4 64p Mulitplayer 1440p 90FOV with minimums always above 60FPS with plenty eye candy turned on. I clocked the i5 750 to 3.8GHz but found this was the bottleneck and I was stuck on low if I wanted to keep the minimum fps up during heavy firefights. BF4 mulitplayer loves cores so X99 it was.
CPU Overclocking
I hadn't clocked a system in 5 years, in fact I'd never even flashed a BIOS so I was starting from scratch. Hopefully this post will be useful to those in a similar position! I conquered the first of the these challenges pretty quick by putting the 1103 BIOS on using Ezflash. No problems.
I initially bought into Asus's 5 way optimisation using the basic instructions given in the "ASUS X99 Software Features & Overclocking" video on youtube. Using the most basic settings I set the optimisation away and it decided on 4.6GHz. The report said all cores at 4.6GHz and "fix voltage 1.22". I though wow!
However, as soon as I launched BF4 I noticed the core voltage was ramping to 1.375V and the fans were getting loud. Not really the amazing overclock I thought it was. I tried a few other settings but found re-running the optimisation seemed to result in hangs when rebooting. In the end I decided to reset the CMOS and do it the old fashioned way.
I read the 5960X Overclocking Guide by Silent_Scone, and watched Linus's video on X99 overclocking and started from there (not sure if i can link?).
I knew my XMP wanted to change the strap to 125 so I manually changed that (XMP still off), upped the voltage to 1.3V fixed and dialled in a multi of 32 for 4GHz which should be safe as houses. I used ROG Realbench v2.4 for stress testing initially 15mins 8GB of RAM. It passed with flying colours so I upped the multi an increment at a time until it ultimately failed at 4.625GHz. I dialled it back down to a multi of 36 (4.5GHz) and started stepping the core voltage down by 0.01V at a time. It eventually failed at 1.25V so I stepped it back up to 1.27V to give a little insurance. Next step was to enable XMP and test and all seemed well and good passing the stress test 1hr 8GB RAM. Temps maxed at 70C - 79C depending on core (is this normal to have 9C variation?)
Problems
So, happy with my overclocking attempts I went into Heaven 4.0 to see how my scores compared with those posted. Benchmark completes fine I exit the program, desktop flashes up and then the screen is black with a mouse pointer, and then it hard locks. I manually reset and get QCODE 96 (PCI BUS Assign Resources) as it just hangs there. After a full power cycle it fired back up again. Not knowing if it was something to do with the GPUs I ran GPU-Z when I got back into windows. It hung on the splash screen, then the system crashed and I restarted. I tried it again and got the message "During previous startup GPU-Z crashed at OpenCL detection. Please update your OpenCL and graphic drivers. Would you like to re-enable OpenCL detection?" If I chose yes it hung, if I chose no it loaded. I ran heaven again, completed a few benchmarks fine and then again black screen on exit. Each time it would hang on QCODE 96 on restart and need a full cycle to get it going again.
Long story short (ish) it was the SA voltage that was at the heart of this. It was set to 0.85 + offset 0.300 for a total of (1.15V), I dialled this back down to 0.85 + offset 0.152 (1.02V) and I've never had an issue since. This voltage is seemingly very important as Silent_Scone keeps pointing out! It controls the PCI Bus Voltage and that must have been the cause of instability.
Where Next?
Given my limited experience and limited gains from cache/RAM tweaking I'm done with pushing the hardware for now. Ideally I'd like to switch from fixed voltage to adaptive/offset to get the idle watts lower (currently around 53W 40C) so I might need some pointers on doing that given that I now know my fixed stable voltage. I haven't done any more stress testing apart from actually playing BF4 and I can say the difference is night and day. Minimum FPS is 100, smooth as, looks great.
TL;DR
5820K (125x36) 4.5GHz, 1.27v VCORE, (0.85 + 0.152) System Agent, 1.9VINPUT, 2666MHz C15 XMP, very happy
