I7 920 D0 20x Mulitiplier vs. 21x Multiplier to hit 4.0Ghz

[irvinparrett]

i7 920 D0 20x Mulitiplier vs. 21x Multiplier to hit 4.0Ghz Which Multiplier Do I use to get to 3.99Ghz or 4.0Ghz 20 or 21. CPU Clock Ratio [21 X]CPU Frequency 3.99GHz(190x21) (if it works I’ll increase Bsck to 190 to hit my 4.0+ overclock. Or, Set the CPU Clock Ratio [20 X] CPU Frequency4.0GHz(200x20). In both Cases I’ve increased [1.40000V] VCore. In both cases should I turn Performance Enhance [Turbo] to Standard? In both cases I’ve Ucore Clock Ratio[x13] 2xMultiplier + 1 to get 13 this is correct right? QPI/Vtt Voltage[1.195V] 1.175V [1.115V] The QPI Link Speed is 7.2GHz on the 20x Multiplier , whereas only 6.84Ghz on the 21x Multiplier? Lower is better right.?

Thanks the noob.

Advanced CPU Core Features
Intel Turbo Boost Tech. [Disabled]
CPU Cores Enabled [All]
CPU Multi-Threading [Enabled]
CPU Enhanced Halt (C1E) [Disabled]
C3/C6/C7 State Support [Disabled]
CPU Thermal Monitor [Enabled]
CPU EIST Function [Disabled]
Bi-Directional PROCHOT [Disabled]
Advanced Frequency Settings
CPU Clock Ratio [20 X]
CPU Frequency 4.0GHz(200x20)
QPI Clock Ratio [x36]
QPI Link Speed 7.2GHz
Uncore Clock Ratio [x13]
Uncore Frequency 2600MHz
BCLK Frequency(Mhz) [200]
Memory Frequency(Mhz) 1066 1200
PCI Express Frequency(Mhz) [100]
CPU Clock Drive [800mV]
PCI Express Clock Drive [900mV]
CPU Clock Skew [0ps]
IOH Clock Skew [0ps]

Motherboard Voltage Control
Load-Line Calibration [Auto]
CPU Vcore 1.23750V [1.40000V]
Dynamic Vcore (DVID) 0.00000V Auto
QPI/Vtt Voltage[1.195V] 1.175V [1.115V]
CPU PLL 1.800V [Auto]
PCIE 1.500V [Auto]
DRAM Voltage 1.500V [1.500V]
DRAM Termination 0.750V [Auto]

Advanced Memory Settings
System Memory Multiplier (SPD) [6.0]
Memory Frequency(Mhz) 1066 1200
Performance Enhance [Turbo]
Dram Timing Selectable (SPD) [Quick]
Profile DDR Voltage 1.5V
Profile QPI Voltage 1.75V
Channel Interleaving 6 Auto
Rank Interleaving 4 Auto
Timing Settings Timing Control
CAS Latency Time 8 9
tRCD 8 9
tRRD 8 9
tRAS 20 24


4.0 Ghz at 21x Multiplier
Advanced CPU Core Features
Intel Turbo Boost Tech. [Disabled]
CPU Cores Enabled [All]
CPU Multi-Threading [Enabled]
CPU Enhanced Halt (C1E) [Disabled]
C3/C6/C7 State Support [Disabled]
CPU Thermal Monitor [Enabled]
CPU EIST Function [Disabled]
Bi-Directional PROCHOT [Disabled]
Advanced Frequency Settings
CPU Clock Ratio [21 X]
CPU Frequency 3.99GHz(190x21)
QPI Clock Ratio [x36]
QPI Link Speed 6.84GHz
Uncore Clock Ratio [x13]
Uncore Frequency 2470MHz
BCLK Frequency(Mhz) [200]
Memory Frequency(Mhz) 1066 1140
PCI Express Frequency(Mhz) [100]
CPU Clock Drive [800mV]
PCI Express Clock Drive [900mV]
CPU Clock Skew [0ps]
IOH Clock Skew [0ps]

Motherboard Voltage Control
Load-Line Calibration [Auto]
CPU Vcore 1.23750V [1.40000V]
Dynamic Vcore (DVID) 0.00000V Auto
QPI/Vtt Voltage[1.195V] 1.175V [1.115V]
CPU PLL 1.800V [Auto]
PCIE 1.500V [Auto]
DRAM Voltage 1.500V [1.500V]
DRAM Termination 0.750V [Auto]

Advanced Memory Settings
System Memory Multiplier (SPD) [6.0]
Memory Frequency(Mhz) 1066 1200
Performance Enhance [Turbo]
Dram Timing Selectable (SPD) [Quick]
Profile DDR Voltage 1.5V
Profile QPI Voltage 1.75V
Channel Interleaving 6 Auto
Rank Interleaving 4 Auto
Timing Settings Timing Control
CAS Latency Time 8 9
tRCD 8 9
tRRD 8 9
tRAS 20 24

 

[bystander]

actually its just me

I agree about turning off turbo, but there can be an exception, which is if you use the x21 multiplier on some motherboards which require it to use that multiplier. If you use any other clock, it should always be off if you are using a high clock.

That is just going off the guides I've read. As in my personal experience, x21 didn't work well.

 

[bigbang]

thats precisely my point... the turbo boost associated with the link exchange is based on distance travelled and is purely logic based, it can never reach 100% stability with it on, it can only approach stability very closely. it is not in anyway similar to your CPU multiplier, because ur cpu has been manufacturer with lithography, there is almost no uncertainty involved.

 

[bigbang]

manufactured*

 

[bystander]

thats precisely my point... the turbo boost associated with the link exchange is based on distance travelled and is purely logic based, it can never reach 100% stability with it on, it can only approach stability very closely. it is not in anyway similar to your CPU multiplier, because ur cpu has been manufacturer with lithography, there is almost no uncertainty involved.

We were actually talking about the CPU multiplier. Or at least I was.

 

[bigbang]

darn!

 

[bystander]

Obviously there is too much disagreement here to be useful, so I advise you just read the guide I posted: http://www.overclock.net/intel-cpus/538439-guide-overclocking-core-i7-920-930-a.html

You can search for other guides too for more info.

Turbo mode – This enables the 21x multiplier on the chip. Most boards allow you to do this with eist disabled, but some boards require it enabled. See if a newer bios lets you change things.

CPU Multiplier – On the 920 the range is from 12x – 21x (22x on one core when at stock speeds). It has been found that the 19x and 21x multipliers are more stable than the 20x.

 

[browsingtheworld]

21x works fine.... if you disable C1E and EIST....

http://www.overclock.net/intel-cpus/724955-how-can-i-get-21x-multiplier.html

It's a good guide but he doesn't say anything about what was stable with C-states on.

 

[bystander]

21x works fine.... if you disable C1E and EIST....

http://www.overclock.net/intel-cpus/724955-how-can-i-get-21x-multiplier.html

It's a good guide but he doesn't say anything about what was stable with C-states on.

It actually did mention it here:
Important to do before you overclock:
EIST – Enhanced intel speedstep technology - It's a power saving tech that should be disabled while testing overclocking stability. This should be disabled while finding your OC, but can be enabled after you are stable (Disable if you have stability issues).

C1E – Another intel power saving technology. Disable while overclocking, enable afterwards.

He suggestion was to only disable while finding your stable overclock, then turn them back on.

 

[browsingtheworld]

Again, he doesn't say what is stable with those settings on like if 21x worked. I can find no evidence of anyone getting a 24/7 overclock with C-states on that uses 21x.

 

[bystander]

You are right. He suggested you test and see how it worked for you.

 

[browsingtheworld]

Assuming you can get your BCLK and IMC stable at 200mhz you can do 19 x 200 for 3.8ghz and run your RAM at 1000mhz. That's pretty high for the BCLK so you might want to start (technically you want to start at 2.8ghz, then 2.9, etc.) at 19 x 185 or 3515mhz.

It's a very good guide but I doubt he bothered to test every little detail like we are curious about here. It could work fine at 21x, I just can't find any evidence that it does.

 

[bystander]

I do know when I OC'ed my system, while following the guide, I did do a search on the subject, and like a link you posted above, I found many people using 21x (the link you posted a bit up there, started off by saying it couldn't, but about half way down the first page, people started coming in saying they were using 21x.

I was curious as to why people were suggesting 21x and 19x. I understood after my searches, or at least understood enough to try, and sure enough 19x worked great for me. Better than 20x.

 

[irvinparrett]

I have been enlightened by all this useful info.
But the main question on the Performance Enhance setting should it be [standard) or[Turbo]
signed the noob.

 

[irvinparrett]

I finally did use the 20x multiplier @ 4.0 and ran prime95 for 2 hours. 38degrees centigrade on idle 78degrees on full load. Looks like we're stable. Are the temps ok. Now what should I increase to get 4.2? The QPI/Vtt Voltage? Should I bump up the VCore Voltage? P.S. Gotta love the Noctua D-14 cooler. Gotta admit researching my settings in the quest for 4.2GHz I haven't run into any problems non-boot issues or bsods. Thanks for all the input. Keep it coming.
the noob.

 

[irvinparrett]

To get to 4.2GHz I first tryed to increase the multiplier to 21x to get 4.2GHz. I then saved to bios and rebooted. In cpuz the clock showed the 20x multiplier. It seems that it would just not accept a 21x multiplier. I then increased only the BCLK to 210 to achieve the 4.2GHz. I saved and rebooted and then cpuz did show the 4.2GHz increase at 20x. Why do you suppose it would not accept the 21x multiplier.
Signed the noob.

 

[bystander]

Have you tried 19x?

As to your question, as the guide I posted earlier mentioned, not all motherboards will allow you to use 21x.

 

[irvinparrett]

I haven't tried 19x but wouldn't that just push the bclk up. I did manage to use the 20x multiplier to push to 4.2 but when i ran prime94 my computer crashed. But, when I just increased the bclk to 205 I achieved 4.1 something and am running prime 95 right now. Prime95 has run about an hour so far. Signs are good. The temperatures at idle are 39, 37, 40, 34 on cores in that order. The temperatures on 100% load are max 82, 79, 79, and 76
signed the noob.
P.S. there shouldn't be any shorter life term on my system running stable at 4.1Ghz or 4.2Ghz right?
P.S. should performance enhance setting be [standard] or [Turbo}

 

[irvinparrett]

I think I get it. performance enhance should be set at [turbo] to use the 21x multiplier.
Am I now getting it.
signed the noob.

 

[bystander]

I think I get it. performance enhance should be set at [turbo] to use the 21x multiplier.
Am I now getting it.
signed the noob.

Yes, this may be the case for your motherboard.

As far as the 19x multiplier goes, from everything I read on the subject, it seems Intel chips work best on odd multipliers. The guide I posted earlier suggests 19x and 21x as the most stable clocks and from personal experience, 19x worked best for me.

 

[irvinparrett]

My next question is how long should I run prime95 (reasonably) to test stability?

Signed the noob!

 

[bystander]

I know a lot of people say 8 hours, but if you read the guide, he suggests 1-2 if I remember correctly. I suggest 30-60 mins before your stable clock and working your way up, then run a 2 hour after you settle on your clocks.

 

[bigbang]

8 hours till u realise u shouldnt run on turbo mode

 

[bystander]

8 hours till u realise u shouldnt run on turbo mode

When using 21x as your multiplier, you aren't really running with a turbo mode, as it never increases, but some motherboards do need it enabled to allow you to use the 21x multiplier. That said, I'd like to see how his system works on x19.

 

[irvinparrett]

I cannot seem to unlock the 21x multiplier to achieve a lower base clock to get to 4.2Ghz. As with the 19x multiplier (settings below) I seem to be stable. I am running prime95 for almost 30 minutes as I type. As you see the QPI link speed is at 7.77, my VCore is 1.40000V. When I try for 4.2Ghz with the 19x multiplier I have to set the bclk at 210. It boots but crashes with prime95. Do I need to raise the QPI/Vtt Voltage[1.195V] 1.175V [1.115V]4.1 GHz to a higher value?

Signed the noob.

Advanced CPU Core Features
Intel Turbo Boost Tech. [Disabled]
CPU Cores Enabled [All]
CPU Multi-Threading [Enabled]
CPU Enhanced Halt (C1E) [Disabled]
C3/C6/C7 State Support [Disabled]
CPU Thermal Monitor [Enabled]
CPU EIST Function [Disabled]
Bi-Directional PROCHOT [Enabled]
Advanced Frequency Settings
CPU Clock Ratio [16 X]
CPU Frequency 4.10GHz(216x19)
QPI Clock Ratio [x36]
QPI Link Speed 7.77GHz
Uncore Clock Ratio [x13]
Uncore Frequency 2600MHz
BCLK Frequency(Mhz) [175]
Memory Frequency(Mhz) 1066 1296
PCI Express Frequency(Mhz) [Auto]
CPU Clock Drive [800mV]
PCI Express Clock Drive [900mV]
CPU Clock Skew [0ps]
IOH Clock Skew [0ps]

Motherboard Voltage Control
Load-Line Calibration [Auto]
CPU Vcore 1.23750V [1.40000V]
Dynamic Vcore (DVID) 0.00000V Auto
QPI/Vtt Voltage[1.195V] 1.175V [1.115V]
CPU PLL 1.800V [Auto]
PCIE 1.500V [Auto]
DRAM Voltage 1.500V [Auto]
DRAM Termination 0.750V [Auto]

Advanced Memory Settings
System Memory Multiplier (SPD) [6.0]
Memory Frequency(Mhz) 1066 1296
Performance Enhance [Turbo]
Dram Timing Selectable (SPD) [Quick]
Profile DDR Voltage 1.5V
Profile QPI Voltage 1.75V
Channel Interleaving 6 Auto
Rank Interleaving 4 Auto
Timing Settings Timing Control
CAS Latency Time 8 9
tRCD 8 9
tRRD 8 9
tRAS 20 24

 

[irvinparrett]

The last settings I used to try to achieve a stable 4.1Ghz clock seemed stable but after 45 minutes of prime95 I crashed. This was only with a base clock of 216 and multiplier of 19x. sorry for the 175 bclk as shown in my settings above. The VCore voltage is at 1.40 it does seem rather high but who am i to know. Any suggestions would be appreciated.
thanks, the noob