what would be considered "normal" voltage(s) for a 975 D0 cpu @ 4ghz w/ HT enabled

[terentenet]

I am trying to overclock this 975 D0 cpu on a Rampage 2 Extreme board. My system is configured as follows.

cpu: i7 975 EE D0
mobo: asus rampage 2 extreme
ram: 12gb corsair 1600 @ 8-8-8-24
storage: 2 x ocz vertex 120gb & 4 x seagate 1tb drives (RAID0)
optical: lg blu-ray rw combo unit
video: 3 x zotac 285 amp!
sound: asus xonar d2 (music and movies) + x-fi titanium fatal1ty pro (games)
enermax revolution 1250w psu

That's most of the system. It's all watercooled, 3 loops, 5 x 480rads, 7 DDC pumps, low noise fans all around. System is very quiet.
This is my first attempt at overclocking an i7 chip. All those voltages and relations between different multipliers just make it seem very complicated for me.

So far, I'm at:
bclk: 200mhz
multi: 20x
HT: enabled
Turbo: disabled
memory: 8x (1600) @ 8-8-8-24 2T
uncore: 16x (3200)
qpi: 7200mt/s
pci-e: 100mhz

voltages:
cpu vcore: 1.26v
cpu pll: 1.84v
QPI: 1.35v
RAM: 1.65

The system is not in my house right now. It's at the company that's building it for me. I was there yesterday, these were the voltages, it was going strong for 8hrs prime95, on all 8 cores.
Temperatures were good, going between 56 and 61 celsius in a 25 degrees ambient.
It was left overnight to prime, I don't know if it made it or not, I should hear from my builder today.

So, how are these voltages? They seem a little high to me, I've seen others with D0's getting to 4GHz with much less (1.20v and less sometimes).

I also uploaded some pics of the system, because I am so proud of how it looks. Please share your thoughts:
http://www.mypicx.com/06202009/i7_975ee/

 

[BTRY B 529th FA BN]

Sorry I can't help you with your voltage question but nice build

 

[terentenet]

A little update, I've heard back from my builder, the system with the above mentioned voltages is 24h prime95 8 cores stable. With no air conditioning and a room temperature of about 30 degrees, the processor was running at about 60-65 degrees (water temperature was 33 degrees).
One thing we don't know.... when we first put in the 975, it started with a default pll voltage of 1.81v and 1.15v on the core.

We set 1.25v on the core and went directly for 4ghz. It ran prime for about 1hr, then locked
Set pll at 1.84v and kept 1.25v on the core, it locked in prime after 2h.
Set pll at 1.86v, 1.25v on the core, it locked very fast, under 30 minutes.
Went back to 1.84v pll and upped core to 1.2625v, stable 24h.

My question is, what's the relation between pll and vcore? Which voltage helps where? Can I decrease the PLL and still maintain stability?
On monday we will start tweaking for 4.4GHz stable with HT on.

 

[imported_Shaq]

Nice rig you got there. 4.4 HT on looks to be the max on water and has been done so that is a realistic, achievable goal. And with a 975 it should be virtually guaranteed since you don't need a sky high BCLK. You will need about 1.4v-1.45v to get there though. You hit the point of diminishing returns at about 4.0-4.1 with most D0's. Some CPU's need more PLL and some don't. I haven't seen any patterns with it. It looks like you can lower it to 1.8 since it didn't help the stability at all.

You might be able to lower QPI voltage also since you don't need a high QPI frequency with a 975. 12GB of ram will stress it but I think you can lower it a tad unless you are going for 2000 or above. lol

Edit: Why are doing a 200 BCLK? You can just raise the multiplier to 27 and keep BCLK at only 163 for 4.4. And you could do memory multi of 10 and uncore 21. That way your QPI can be a little lower. 1.35v is max set by Intel and it is better to keep it a little lower especially with an expensive CPU.

 

[aigomorla]

dude id hate to see the price tag on that system if u didnt build it yourself.

But its definitely aigo aproved!

 

[daw123]

Originally posted by: aigomorla
dude id hate to see the price tag on that system if u didnt build it yourself.

But its definitely aigo aproved!

I'd hate to see the price tag, even if I was building it myself.

Nice rig though.

 

[VirtualLarry]

Sweet rig. I do want to see the price tag on that sucker though. Is it over 5 Gs?
Does the builder warranty the overclock?

 

[terentenet]

Originally posted by: aigomorla
dude id hate to see the price tag on that system if u didnt build it yourself.

But its definitely aigo aproved!

Thanks all for your kind words! I hope I can reach a bit higher on this chip, with HT enabled. I do have a feeling that a X58 Classified board would do a bit better though. I've spent alot on this system... mostly because it's been in the works for more than 6 months. Most of the components I started with are now sitting aside. Most of the components were bought just as they came out, so they were all bought at their highest price.
The concept was different when I first thought of this system. I thought I would do SS phase change on the CPU and chill the GPU water loop. I had Dimas build me a custom SS phase change unit, with a water chiller. I have the unit, it's working like a charm and it's just sitting and collecting dust because meanwhile I decided I want a quiet system. So I ditched the phase change and went for full watercooling.

Just a thought, I started working on this multi rad setup thinking i would be able to use ultra low speed fans, under 1000rpm. I ended up spinning all 20 Noctua NF-P12 1300 fans at their full speed. On the CPU loop there was a temperature drop going from 900 to 1100rpm (not big but it was there 100%, 2-3 degrees during full load), no significant temperature drop to 1300rpm on the CPU loop. The GPU loop makes a difference between 1100rpm and 1300rpm. Full load (furmark) temps on all 3 GTX285 AMP! cards dropped from 55 celsius @ 1100rpm to 51 celsius @ 1300rpm. It's amazing what watercooling can do... my current GTX280 cards are idling at 57 degrees and put out up to 96 degrees in furmark. Not to mention the noise they make, even when idle.

 

[terentenet]

Larry, it's more than 5Gs. Not sure how much more, I'm really afraid to make a calculation. But here goes nothing... 1G for the cpu, 1G for 2 SSDs, 1.1G for 3 video cards, 1.4G for 5 rads and 20 fans, 1.5G in cooling blocks and pumps+tops and there's 6Gs.
We still have to add R2E mobo, 12Gb Corsair ram, 4 more 1tb HDDs, 2 sound cards, 2 lian li cases, 1PSU, lots of fittings, 3 reservoirs, 2 bitspower power stations, lots of tubing (more than 32 feet of tubing inside there), lots of sheets of aluminium, aluminium profiles, plexiglas, mesh panels.


Shaq, I will take your BCLK advice into consideration when going for over 4GHz. I do like the round numbers of 200x20 for 4GHz though. I will try to lower the QPI a bit, I will try with PLL lower as well. I will save those settings for reference and 24/7 use. I will try different routes to reach more than 4GHz with HT enabled, including playing more with the multipliers, although this D0 chip seems to like high BCLK values.

 

[Phew]

Money well spent, that's a work of art.

 

[imported_Shaq]

Any updates yet?

 

[terentenet]

Shaq, the system is with me now, I took it home early. I am currently still at 4GHz, 24h Prime95 stable and I think 24h Prime95 + Furmark stable. The voltages are almost the same as in the 1st post. The CPU wanted one more step for Prime and Furmark to run stable at the same time. But it does work indeed.
I am just getting around to setting up the SSDs, HDDs, set partitions and install the OSs. After all that is done, I will start some more tweaking.

 

[richierich1212]

Wow nice system

 

[lopri]

More money than brain....


I kid! I kid!

That's a heck of a system you've got there. I especially like the even numbers for the overclock. (20x200) Very nice!

 

[imported_Shaq]

Originally posted by: terentenet
Shaq, the system is with me now, I took it home early. I am currently still at 4GHz, 24h Prime95 stable and I think 24h Prime95 + Furmark stable. The voltages are almost the same as in the 1st post. The CPU wanted one more step for Prime and Furmark to run stable at the same time. But it does work indeed.
I am just getting around to setting up the SSDs, HDDs, set partitions and install the OSs. After all that is done, I will start some more tweaking.

Well I hope you aren't going to waste all of that just for 4Ghz. So you need 1.27v for 4Ghz? 4.4 with hyperthreading is going to put it over 1.4v for sure, I would guess about 1.45v. That is still well within max spec however and with all that cooling your temps should stay under 60C with normal loads. Or are you going to leave it at 4.0? I assumed you were going to go higher, but all of that extra stress to make it 10% faster may not be worth it. If you do stay at 4.0 you should be able to lower qpi and pll.

 

[terentenet]

Shaq, I've seen many increase the PCIe clock by a few MHz. It was said it would help obtain higher clocks. What clocks can you increase by increasing the PCIe? I am still at 100MHz.

 

[imported_Shaq]

It will help you raise BCLK by upping PCIE frequency. After you determine your max BCLK of the motherboard/CPU. You only need a few Mhz, like up to 103-106 but some motherboards, like mine, don't like it raised at all. It won't even boot. I believe it helps for the max motherboard BCLK and not CPU. With a 975 you can raise the CPU muliplier so you don't need to do that. That is the only reason to get the 975 is for the unlocked mulipliers...and e-peen of course. lol Just crank up the multiplier and run at 160 BCLK (27-28 multi will put it around 4.4), 10x memory and 21X uncore.

Lower BCLK's allow you to run a lower QPI voltage, and since 1.35v is max I try to keep it below that. And with 12GB at 1600 frequency you are stressing the memory controller quite a bit. QPI voltage is for the memory controller, QPI bus and cache. I'm trying to help your CPU last longer since it is about $1200. Also if you lower the QPI speed you can tighten the memory timings at the same relative QPI voltage. For example, instead of 8-8-8-24 2T at 200 BCLK you might be able to pull off 8-7-8-22 1T at 160 BCLK at 1.3v QPI...just an example. It will be slightly faster and at the same/lower voltage.

 

[thilanliyan]

That's a nice system...only things I don't like are the external reservoirs. Just a personal preference...I keep it all internal.

 

[aigomorla]

Originally posted by: lopri
More money than brain....

i thought that only applied to me?

LOL

remember i got 3 4.4ghz monsters in my collection... a W3570 which isnt including in my list below also.

 

[AdamK47]

I have similar settings for my much cheaper D0 920. I have a CoolerMaster V8 heatsink/fan for the CPU. The motherboard is an Asus P6T Deluxe (version 1). The memory is 6GB Patriot PC12800. Everything is in an Antec 900 case. The rest of my specs can be seen from my sig link.
Using your rundown as an example I'm at...

CPU Clock: 4000MHz
BCLK: 200MHz
Multiplier: 20x
HT: Enabled
Turbo: Disabled
Memory: 8x (1600) @ 9-9-9-24 1T
Uncore: 16x (3200)
QPI: 7200MT/s
PCI-E: 105MHz

Voltages:
CPU VCore: 1.35V
CPU PLL: 1.90V
QPI: 1.40V
RAM: 1.60V

I've had it overclocked to this since Thursday. So far everything has been 100% stable after 24 hours of Prime95, 12 hours of MemTest, and 300 loops of the Crysis CPU1 test.

Not bad for a CPU I bought for $240 at MicroCenter. I sold my C0 920 for a very cheap $150 the same day on these forums.

 

[terentenet]

Nice overclock Adam! You should really try Furmark and Prime95 at the same time, aim for 24h stability. Start Furmark, set it to Stability testing, set 1280x1024 res, 4x AA, start process manager, set Priority to High, Affinity to one of the cores, then start Prime95 and Blend test. If you can keep it 24h like that, it's rock solid. This test will stress the CPU, Memory, GPU, PSU at the same time. For example, I needed to raise the Vcore from 1.26v to 1.27v to maintain stability (it crashed after 15h).
My setup needs about 1 - 1.1kW in this test. Everything gets hot; CPU to about 70 degrees, GPU 58 degrees, NB and SB both at about 45 degrees. PSU starts spinning @ max and blows hot air. That's the ultimate test.

 

[deputc26]

Are you'are 285s at stock? (702 I think?) and at 1-1.1Kw you paid ~$2.40 to stress test you're sys for 24h (assuming electricity is 10c/Kwh but it could be as high as 20c or as low as 6c). That is pretty insane.

Beautiful rig, any chance of pictures when you're done?

 

[AdamK47]

I just noticed the link to your rig pics has the chance of not being safe for work.

 

[aigomorla]

Terent try this.

Vcore 1.375
QPI: 1.375
VTT: +175 (you want VTT to be like 1.35)
DRAM: 1.65

http://i125.photobucket.com/al...enchmarks/newstats.jpg

Lets see if your retail is better then my ES.

 

[terentenet]

Originally posted by: aigomorla
Terent try this.

Vcore 1.375
QPI: 1.375
VTT: +175 (you want VTT to be like 1.35)
DRAM: 1.65

http://i125.photobucket.com/al...enchmarks/newstats.jpg

Lets see if your retail is better then my ES.

Aigo, that's nice ) and preety cool running. I do run in a warm ambient with A/C unit not on all the time. My ambient is 28 degrees (82F). My CPU temps reach 70 degrees now, at 1.27v.
Can you please give some details on the cooling you have on yours?
I will try those settings tonight, maybe it will work. I will make that run with A/C on to help the cooling system.