Noob questions i7 920 Overclock

Hey All,

So I am trying to read up and understand how all of these settings effect each other. My goals are to learn, then achieve a moderate but stable OC to run with 24/7 and play games.

For those who haven't seen one of my other posts.

I have an Antec 300
2 Front intake fans
1 Rear exhaust fan

i7 920
TRUE 1366 RT 1 fan pushing exhaust through to the rear fan.

On an ASUS P6T Deluxe v2
6g Corsair XMS 1333 9-9-9-24 Advertised timings.
EVGA GTX 260 216 Core
Corsair 650TX PS
2x Seagate 7200.12 500G Sata Drives
1x Samsung CD/DVD SATA

I see lots of mention of changing various voltages but I don't understand is how the voltages impact overclocking, what does raising or lowering the voltages achieve?

CPU RATIO
I know this * BClock = CPU speed

BCLCK (CPU Host Freq)
I know this * CPU Ratio = CPU speed, I also know this affects the memory multiplier.

PCIE
Option 100-200, I dont see much mention of anyone changing this.

DRAM

I know this effects the memory speed but the options increase as I increase the bclock

UCLK ( Uncore)

I dont know what this effects but I know the options increase as I increase the bclock

QPI

I dont know what this effects but I know the options increase as I increase the bclock


===
What I have done so far, isn't much.

With BIOS defaults, I Disabled Speedstep and C1E. To prevent auto Throttle.

At the moment as a small step I changed

CPU Ratio from Auto to 20
BCLOCK from Auto to 150

Left PCIE, DRAM, UCLOCK, QPI on Auto

And heres what I have so far after 20 minutes of prime running 8 small FFT's



I do notice the memory is actually still underclocked if I am not mistaken.
Running at apx 1200 8-8-8-20
Specd at 1333 9-9-9-24

Though I am wary to do much more trial and error without a better understanding of how each setting impacts the others.

This is where I hope you will come in

Thanks

I have practically the same BIOS and tackled the issues you speak of here:
http://www.ocforums.com/showthread.php?t=595403

c627627 said:

I have practically the same BIOS and tackled the issues you speak of here:
http://www.ocforums.com/showthread.php?t=595403

Click to expand...

Yes very very similar excellent bit of information I will have to digest it all and get back to you with questions.

Yeah, post there if things are not clear, I've learned quite a bit since then.

Lower your multiplier and find out your max BCLK...

c627627 said:

Yeah, post there if things are not clear, I've learned quite a bit since then.

Lower your multiplier and find out your max BCLK...

Click to expand...

Ok, but why is this important?

Why is it better to have a :

Higher BCLCK and Lower CPU Ratio
--------------VS----------------
Higher CPU Ratio and Lower BCLCK

Because BCLCK increases CPU frequency. Low ratio keeps your RAM running at reasonable speeds so it won't die out in the process of OCing.

BG-0 said:

Because BCLCK increases CPU frequency. Low ratio keeps your RAM running at reasonable speeds so it won't die out in the process of OCing.

Click to expand...

Ok.

I thought:

Base Clock X Memory Multiplier = Memory Clock x 2 = Memory Speed

So where does CPU ratio come in to effect memory speed?

i.e (Assuming a ratio of 2:8 I think it is..)
=============== 2.6 Ghz
133 * 20 = 2666 (or there abouts)
133 x 4 = 532 * 2 = 1064 (or there abouts)

=============== 3.0 Ghz
150 * 20 = 3000 (or there abouts)
211 x 4 = 544 * 2 = 1688 (or there abouts)

=============== 4.0 Ghz
200 x 4 = 800 * 2 = 1600 (or there abouts)
200 * 20 = 4000 (or there abouts)

higher BLCK means higher QPI speeds depending on the ratio you use. since BLCK isnt the same as LGA775 fsb i cant see why higher BLCK is required. since it has been shown that higher QPI speeds dont help i7. on the other hand if you get a board that doesnt have a ratio to run your ram at spec, you would need to use a higher BLCK. the BLCK effects ram speed based on ratio. the cpu ratio doesnt effect memory speed...

Huserx said:

Ok, but why is this important?

Why is it better to have a :

Higher BCLCK and Lower CPU Ratio
--------------VS----------------
Higher CPU Ratio and Lower BCLCK

Click to expand...

Evilsizer said:

higher BLCK means higher QPI speeds depending on the ratio you use. since BLCK isnt the same as LGA775 fsb i cant see why higher BLCK is required. since it has been shown that higher QPI speeds dont help i7. on the other hand if you get a board that doesnt have a ratio to run your ram at spec, you would need to use a higher BLCK. the BLCK effects ram speed based on ratio. the cpu ratio doesnt effect memory speed...

Click to expand...

High BCLK in and of itself is not vital. The reason there is so much attention on having a high BCLK is that only 965(soon 975) have unlocked multi's. From what I have understood multi's of 24-27 are very favorable.

Since the rest of us only have 21(20+T) or 23(22+T) than we have little choice but to push our BCLK in order to achieve higher cpu clock speeds.

I have yet to see anyone show that a processor is faster at a given clock speed based on BCLK alone, not saying it hasn't been done, just haven't seen it yet.

21*181 = 3800+ but you may have your ram at 1086 or 1448 or 1810 and that may have an effect on some memory dependent benchmarks in comparison to something like
20*190(1140/1520/1900 mem speeds) or even 19*200(1200/1600/2000).

Just my 2c on it though because I haven't done any testing to that effect either tbh.

on the same page with you n3buchan3zzar...

Hey All,

So lastnight I adjusted a few settings with a goal of achieving a stable 3.5GHz OC.
It seemed stable at first, temps on prime for about an hour were around 65-66c.
I was able to play a few hours of WOW, then started prime on small before going to bed.

Prime95 Ran for 4 hours before the system appears to have re-booted.
Temps logged by real temp averaged 66-68c

The settings I have are:
===================
*Apx - Denotes approximation I don't have the exact bios figures in front of me.

Speedstep [Disabeled]
C1E [Disabled]
Marvell Controller [Disabled]

CPU Ratio [19]
BCLCK Frequency [175]
DRAM Frequenct [DDR3-1400 MHz] *Apx (9-9-9-24 Timings)
UCLK [2800] * Apx
QPI Link Data Rate - Lowest setting Around 66xx or 68xx I cant recall exactly this morning.
CPU Voltage [1.225]
Load-Line Calibration [Enabled]

Everything Else is on [Auto] or System Defaults.

===============

So what should I try next:

1) Raise the Vcore more.

2) Manually set and raise the DRAM BUS Voltage [Stock is 1.5v I think] and QPI/DRAM Core Voltage [Not sure what auto sets it to].

3) Downclock the RAM.

4) A combination of the above.

c627627 said:

Yeah, post there if things are not clear, I've learned quite a bit since then.

Lower your multiplier and find out your max BCLK...

Click to expand...

This is still solid advice just to know where your chip ends. BCLK maximums are mostly cpu dependent from my research, the board only affects the last few ticks in most cases. A few who have multiple i7 rigs have reported that max BCLK are almost identical from mobo to mobo with only small variances.

BCLK testing is done at a low multi like 12x with the ram underclocked too in general.

Next I would try to find where your Ram can run comfortably. Odds are that you will either OC or underclock your ram unless you can hit a perfect BCLK/divider setting. It's good to know that your ram can run at xxxx speed so you know when you HAVE to drop your multi.

Huserx said:

Hey All,

So lastnight I adjusted a few settings with a goal of achieving a stable 3.5GHz OC.
It seemed stable at first, temps on prime for about an hour were around 65-66c.
I was able to play a few hours of WOW, then started prime on small before going to bed.

Prime95 Ran for 4 hours before the system appears to have re-booted.
Temps logged by real temp averaged 66-68c

The settings I have are:
===================
*Apx - Denotes approximation I don't have the exact bios figures in front of me.

Speedstep [Disabeled]
C1E [Disabled]
Marvell Controller [Disabled] - this just disables the Marvell SATA ports, not sure if you need this disabled

CPU Ratio [19]
BCLCK Frequency [175]
DRAM Frequenct [DDR3-1400 MHz] *Apx (9-9-9-24 Timings)
UCLK [2800] * Apx
QPI Link Data Rate - Lowest setting Around 66xx or 68xx I cant recall exactly this morning.
CPU Voltage [1.225] - You will most likely need to raise this of course as you scale higher, you will have to decide what is comfortable to you and it will depend on your cooling predominately
Load-Line Calibration [Enabled]

Everything Else is on [Auto] or System Defaults.

===============

So what should I try next:

1) Raise the Vcore more. - like said above

2) Manually set and raise the DRAM BUS Voltage [Stock is 1.5v I think] -This is your Ram voltage, start with what the manufacturer recommends and if you are over their speed you may need to raise it. Make sure that this setting is NO HIGHER THAN .5V GREATER THAN YOUR VTT(thats qpi/dram)

and QPI/DRAM Core Voltage [Not sure what auto sets it to]. This is your vtt voltage or Uncore voltage. Default may be anywhere from 1.10-1.20+ or more if you have XMP memory as that can set both vdimm and vtt voltages. The key is to keep this voltage WITHIN .5V OF YOUR VDIMM. I've now said that 2x because it is a vital bit of information.

3) Downclock the RAM. - By all means. For exploratory research you want everything else underclocked when finding your theoretical maximums...not that I always take my own advice but in general it's good policy to find the individual maximums, then see where they can all meet.

4) A combination of the above.

Click to expand...

In most cases getting to the mid 3.xGhz is relatively easy. Some can do it with nothing more than a vCore setting change. 4+ seems to get harder. Where do you aim to be at? Are you looking for just a little bump to run 24/7? Are you interested in bench/suicide run settings? Do you want HT enabled or are you willing to drop HT for some more Mhz? Just curious as those questions decide what to do next.

Where do you aim to be at?

Click to expand...

My aim is to be at 3.5 I would be happy with that.

Are you looking for just a little bump to run 24/7?

Click to expand...

Yes basically.

Are you interested in bench/suicide run settings?

Click to expand...

No

Do you want HT enabled or are you willing to drop HT for some more Mhz?

Click to expand...

Enabled

BCLK testing is done at a low multi like 12x with the ram underclocked too in general.

Click to expand...

Ok so how does one best go about BCLK testing?
Start at a low multi like 12 or 14x then raise the BCLK in what incraments?
How does one test each increment and for how long?
24 hrs of prime 95 for each increment?

…Try to find where your Ram can run comfortably?

Click to expand...

Ok, how so? What in your opinion is the best process to do this?

I know at this point this seems to be turning into a whole new conversation.. But I appreciate the input.


Thanks again.