Strange results while overclocking... any ideas?

Arachnae

Arachnae

Arachnae

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Joined
16 Sep 2009
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Milton Keynes, Bucks
I'll start off by admitting I've not really overclocked before, nothing significant anyway..

Here's what I've got and what I've done..

My system:
Intel core i7 920 D0
Asus P6T SE
Corsair 6GB triple channel for i7 1600Mhz, 1.65V.
Sapphire HD4870 1GB Vapor-X.
Antec 900 case.
Stock cooling on the cpu and I'm running windows 7 x64 professional.

I first used ATI Catalyst to overclock my graphics card from 500 gpu, 900 RAM to 800GPU, 1100RAM. I noticed here that the gpu would keep saying it's 500mhz no matter what i changed it to, so i switched to using Rivatuner which "solved" this.. though I now understand that the 500 catalyst was reporting was the 2D, idle readout, not the total capable. With Rivatuner, the exact numbers are 806 Mhz and 1101Mhz.

I also noticed my system RAM wasn't running at full speed, so I set the bios settings to manual and set the speed to "DDR3-1600Mhz", set the QPI/DRAM core voltage to 1.35V and the DRAM Bus voltage to 1.64V.

Everything boots up fine.

At all default/auto settings, my system benches with 3dMark06 at 14015.
With the altered RAM settings and gpu overclock, I reach a score of 14733
This isn't really what I expected since the apparent average score according to 3dmark results page for my specs is around 15100. I'm not sure if this an average of previous benches, or stock settings or OC'd settings.

Anyhow, I decided it was time to OC my cpu to see what it could do.

First I changed the BCLK to 20x140 from 20x134, it booted up fine.
I then pushed my luck a bit and went to 20x150, which it didn't like as much and although it booted fine, prime 95 was failing almsot instantly..
I dropped it to 21x140 and prime95 seemed fine, did a 3dmark benchmark.. and my score came out at under 12000.
Switching back to standard 20x133 brings it back up to 14700ish again.

Here's where I'm struggling to understand what is going on..
How did I managed to drop by 3000 3dmark points by increasing my cpu frequency? While doing the 3dmark06 test, while overclocked the framerates are sometimes more than 10% lower, for example in the last test with all of the snow/ice, i don't drop below 80fps while using the standard clock.. but while overclocked in the way i mentioned it doesn't even hit 70.

Any ideas?
 
Hi Arachnae

welcome to the forums :)


dependant on your cooler i would go for 180Xauto cpu ratio for 3.8

or 191Xauto cpu ratio for 4ghz

only do this if temperatures are good under load [below 85'c is what you are aiming for]


pci frequency needs to be 101

if you set the qpi/dram voltage to 1.325 you should be fine with that

put the dram bus voltage to 1.66v [it will warn you but will be fine]

cpu differential amp to 900mv

cpu core to around 1.275 [then work the voltage down in stages until you reach the least stable voltage]
cpu pll - to the first yellow value

remember to set your ram timings

this is all off the top of my head so the settings wont be in order - but should be all you need to get it clocked and stable
 
Is it possible that after the Prime failure you reverted all the OC settings to failsafe defaults? That might be why you experienced a performance drop.... Its just a guess though

Try loading optimised defaults [I'm working off my ex58-ud5 here, where i have that option, so sorry if this doesnt apply, as i've never used a P6T SE]
 
I'll apologise for seeming completely noobish, but I guess that's just what I am.. but hey everyone starts somewhere. I think I was also a bit naiive when I came to overclocking forums with these problems, I hadn't done much research on it myself, and slowly as I posted my problem on more forums I had more details to give to people lol. I now realise that a 3dmark score of near 15000 isn't as bad as I thought it was, I guess I just saw the average for my setup and freaked, not realised that half of these that made up the average will be heavily overclocked by people who know what they're doing.

Rjkoneill: With my baseclock so high, would I also need to bring down the ram multiplier so I don't fry it? I'm also certain than I have no idea what I'm doing with regards to setting ram timings. At the moment they appear to be auto set to 9-9-9-24 by looking at the BIOS.

I'm using the stock cooler for now, so I'm not after an extreme overclock, especially since this is my first foray into OCing, somewhere around 3.4-3.6 would do me just fine tbh, though I'm hoping my nice and cool case will help take the strain off of the cpu cooler a little. With the numbers I used, 3Ghz pulled me up to 75 degrees under prime95 testing with 20x150, and strangely (to me anyway) 72 degrees when at 21x140, 60Mhz = 3 degrees? :P

griffo: I'm certain that it hasn't loaded optimized defaults as I went back into the bios and set the bclk back down to 133 myself, and all of the other changes were present.

It's been suggested that the performance drop might have been the graphics card overclock being unstable, but I'm not sure how that would hold up since it seemed to work fine without the cpu overclock..

If someone could help me out with ram timings and multiplier settings i'd be very grateful

In the meantime I'll try the OC I put on the cpu before and bring the gpu back down to see what happens.
 
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I'll apologise for seeming completely noobish, but I guess that's just what I am.. but hey everyone starts somewhere. I think I was also a bit naiive when I came to overclocking forums with there problems, I hadn't done much research on it myself, and slowly as I posted my problem on more forums I had more details to give to people lol. I now realise that a 3dmark score of near 15000 isn't as bad as I thought it was, I guess I just saw the average for my setup and freaked, not realised that half of these that made up the average will be heavily overclocked by people who know what they're doing.

Rjkoneill: With my baseclock so high, would I also need to bring down the ram multiplier so I don't fry it? It's currently set at DDR3-1600Mhz @ 133 BCLK, should I set it back to auto for doing this? I'm also certain than I have no idea what I'm doing with regards to setting ram timings. At the moment they appear to be auto set to 8-8-8-24 by looking at the BIOS.

I'm using the stock cooler for now, so I'm not after an extreme overclock, especially since this is my first foray into OCing, somewhere around 3.4-3.6 would do me just fine tbh, though I'm hoping my nice and cool case will help take the strain off of the cpu cooler a little. With the numbers I used, 3Ghz pulled me up to 75 degrees under prime95 testing with 20x150, and strangely (to me anyway) 72 degrees when at 21x140, 60Mhz = 3 degrees? :P

griffo: I'm certain that it hasn't loaded optimized defaults as I went back into the bios and set the bclk back down to 133 myself, and all of the other changes were present.

It's been suggested that the performance drop might have been the graphics card overclock being unstable, but I'm not sure how that would hold up since it seemed to work fine without the cpu overclock..

If someone could help me out with ram timings and multiplier settings i'd be very grateful

In the meantime I'll try the OC I put on the cpu before and bring the gpu back down to see what happens.

Updates:

just fyis, the first yellow cpu pll value is 1.92V
 
Quick update:

I pushed my graphics card down to 790 gpu 1100 ram, using the CCC.
With standard cpu settings this brought me a score of:
14684 3DMarks
SM2 5270
SM3 6975
CPU 4774

After that i pushed up the DRAM voltage from 1.64 to 1.66 and pushed my bclk up to 141 from 134.
Results:
15015 3DMarks
SM2 5308
SM3 7154
CPU 4986

more to follow.. any input would be great :)

Seems 150 BCLK with my current settings the same was enough to force a reboot when the cpu tests came, though I could tell that things were running faster up until that point.
 
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get a titan fenrir, corsair H50 or similar cooler and whack those settings in - your chip will be fine

any 920 D0 can do 4ghz easily and safely with the right cooling
 
I just threw the settings in with what I have, and asus probe started its warning siren pretty quickly after i started a prime95 run! It was however stable though hot :P

I dropped it down to 170 BCLK for now and the cpu voltage to 1.256V.

It's appears stable, I'll check the temp :) update: eventually reaches 78 degrees and starts getting complained about, no prime95 warnings though, i've dropped the voltage down to 1.25. update 2: 76 degrees and stable at 170 bclk and 1.25V.

Also, you convinced me to get the H50.. the reviews on it said it was the smarter option for the cost. Shame I had to use saturday delivery :(

also, any chance someone can give me some pointers about memory timings? :)

Another update: I've managed to drop it to 1.18750Vcore and its stable, maxing out at 74 degrees. I'm gonna keep dropping it bit by bit to see what i can get it down to. Now down to 1.15Vcore, it appears stable too.

i think i need to run prime95 for longer as i get to the thresholds :)


Vcore 1.125V was the lowest i could go without bsods or prime95 errors at 3.4Ghz on a stock cooler, is that any good?
 
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ss1.jpg

ss2.jpg

ss3.jpg


How does that look so far, what are the odds of me blowing up my pc? :)

Latest 3dmark with the above settings and GPU @ 900, RAM at 1100Mhz gives

15745 3DMarks
SM2 5402
SM3 7315
CPU 5976

That any good?

edit: not sure why 3dmark thinks my 920 is a 975extreme :/
 
I left some videos encoding last night and returned to a frozen pc, not as stable as I thought I suppose.. I upped the voltage back up to 1.15 and it didn't throw up any problems, but where before the overclock, the encoding program was using 100% of my CPU power, it was only using 30% while OC'd...

Back to the drawing board I guess.. even with the cpu clocked down again it's still only using 57%.. maybe it's because I left my RAM on manual settings?

I think I'll have to wait until my watercooler arrives before I ramp up the numbers again :)
 
Okay so I've strapped my watercooler in, installed my RAID and windows, got the basic ocing apps..

But I'm having trouble getting a working 4Ghz clock..

I'm currently at the suggested settings above, but its an alsmot instant bluescreen on prime95 with the error machine check exception.

I've tried 200x20, 181x21 even 210x19, and still nothing, thats as far as the bclks go.. ive tried upping the cpu voltage and qpi voltage to no avail.

Any ideas what im missing?
 
Yeah with ram above clockspeed it wont even load vga output, let alone windows.

Currently im at 1.66V and 1531mhz for the ram.

running at 191 x 21 for my cpu speed.

my cpu voltage is 1.28750 with qpi at 1.325 and pll at 1.92.

ive got differential amp at 900mV.

my UCLK and QPI link data rate are set manually.

At these settings it was stable in prime for about 20 mins before bluescreening with machine check exception, any ideas?

Edit: i realised that i wasnt watching temperatures during my 20 min prime fail, but looking at them right now theyre pretty decent... hovering around 75-76 degrees.
 
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Drop the PLL down back to 1.8v, no need for it to be that high.

MACHINE_CHECK_EXCEPTION BSOD's for me have generally been not enough vcore, give it a couple of nudges and retest
 
checking out the changes suggested.

stable so far, prime95 brings it up to 80 degrees on load.

Managed to get 17959 in 3dmark06, is that decent for my setup?
 
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