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

irvinparrett

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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
 

browsingtheworld

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The 920 doesn't have turbo.

To get a higher clock speed with a lower multiplier means you have to have a higher BCLK. In this case 20 x 200 or 21 x 191. With the multiplier at 20 you can run your RAM at 1600 mhz or 2000 mhz. With the Multiplier at 21 you can run your RAM at 1528 mhz or 1910 mhz. I would choose the multiplier that lets you run your RAM the fastest that the RAM allows (or SPD).
 

irvinparrett

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Don't I have to run my ram (TR3X6G1333C9) Corsair DDR3 Memory.SPD Latency: 7-7-7-20
Tested Latency: 9-9-9-24
Memory Type: DDR3
Speed Rating: PC3-10600 (1333MHz)Tested Speed: 1333Mhz
6GB XMS Memory kit for triple channel systems, 1333MHz, 9-9-9-24, 1.5V
2 triple channel kits for 12GB total memory.
at less than 1333MHz and do I set the latency at 9-9-9-24 or tighter?

thanks the noob
 

browsingtheworld

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You're never going to notice the different in CAS latency unless you're running benchmarks. RAM speed doesn't do anything for gaming except for loading in which case you'll be limited by your HDD.
 

bigbang

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ehem i was referring to Performance Enhance [Turbo], which is an option for the memory. no cpu's have turbo so that was just retarded comment.
cas latency defines the rate at which new items are allocated in ur ram matrix. it does affect overall processing speed but not as significantly as does FSB, because FSB directly affects the number of sequence intructions being processed each second.
In High detailed first person shooters where ur cpu is being bottlenecked constantly, u will notice a huge difference between cas 7 and cas 9, in that cas 7 lifts up ur minimum framerates. ur cpu will be more free in assigning new areas for processing rapid movements of the mouse correlated to the gfx data.
so yes if u are able to boost it to cas 7, i dont see why u shouldnt have it on, but doing so will significantly reduce ur ability to increase urclock rate, which decreases ur average fps
 
The i7 seems to overclock best on an odd multiplier. Some motherboards do not allow x21 without having their turbo mode enabled, others will allow it without enabling turbo mode (mine didn't require me to turn it on, but I later realized that it automatically turned it on). And yes, the i7 920 has a turbo mode or to phrase it properly, "Intel Turbo Boost Tech".

While searching around, I learned that the i7 920 and apparently most intel chips, overclock best on odd multipliers. That leaves a multiplier of x19 or x21. Some people are having better results at x19 and others at x21. For myself, I was able to be stable at x19 up to 4.2Ghz and 1.35 vcore, but I had problems at x21 at 4.0Ghz.

Anyways, rather than listening to me, you might want to read this guide instead: http://www.overclock.net/intel-cpus/538439-guide-overclocking-core-i7-920-930-a.html
 

browsingtheworld

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:lol:
The turbo mode itself is not inherently unstable as you suggest, it just allows you to run your RAM at 10x multiplier instead of 8x. If your BCLK is say 100 it's not going to cause instability.

But yes, the 920 does have turbo so the 21 multiplier will not be stable.

You can do 200x20 with 1000mhz RAM or 19x211 with 1266mhz.
 


That's not necessarily true. It is something you need to just test for each i7 920. They all behave slightly different and it also depends on the motherboard.

Some give you access to x21 without enabling Turbo boost. Some let you set it to x21 with turbo boost, but then turbo boost does nothing. Others can't use x21 due to their motherboard not allowing you to.

The stability is also just random depending on your chip. For me, x21 ran hot and ultimately unstable, but x19 was better than both x20 and x21.
 


The guide I posted does mention it: http://www.overclock.net/intel-cpus/538439-guide-overclocking-core-i7-920-930-a.html

But the reason it's bad, is because when you go from x20 to x21, it increases power and heat from the base line. However, if you start at x21, then it doesn't matter, because it will not go higher, but not all motherboards let you use it as your as your default.
 

bigbang

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i think the turbo boost option for memory is designed for the automatic overcloking profiles and is unholy.death to turbo boost!
i had no intentions of talking about intel's turbo nor did i know it existed
 

browsingtheworld

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You're talking about a few ASUS boards that does it and I'm not even sure about that. I can't find any evidence of anyone getting a stable OC on their turbo multiplier at OCN.

You definitely can't get a stable overclock with C-states enabled using the turbo multiplier and who really wants to run a CPU at it's maximum speed 24/7.
 


I think you misunderstand what it does. It doesn't run at max speed 24/7, even if you use the x21 multiplier. It still has step up enabled. Your clock will drop to half unless it has a load.

And like I said, it doesn't work well for me, as I did attempt it, but I got better OCing at x19. Better than x20 as well. However, it still dropped to half clocks when it wasn't pushed.
 

browsingtheworld

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Yes it'll be functional in the sense that it shows up as 21x on CPU-Z but it does kick in it'll draw an excessive amount of power since C-states are enabled and the CPU determines it's own power requirements. When it notices that you're using the turbo multiplier because you used it to overclock it'll either draw more power than you want or crash/error when it realizes it doesn't have sufficient power.

You can get it to boot but it won't be stable.
 


Here I thought you might listen to what's written in the guide, since you changed your stance on turbo mode existing. I guess you are as stubborn as ever.

From the guide I posted earlier: 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.
http://www.overclock.net/intel-cpus/538439-guide-overclocking-core-i7-920-930-a.html

In my case, I was perfectly stable at 3.8ghz with x21, but x19 let me go higher.
 

bigbang

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ok this is what i think. i just wanna say it cause i like typing stuff and being involved...
turbo mode apparently increases access rate at the cost of signal width. however once u overclock the system the proportionality factor increases causing the signals to no longer make sense to the cpu. as the result the cpu tags a "this is not what i wanted" flag on each bit that doesn't seem like the original signal, and u get loads of errors while processing (confirmed with prime95)
at least this is what happens to me when i turn turbo boost on, call me crazy :|
 


I didn't say you should. I said that x21 can be stable, you are saying no. The guide says yes. You say no.

Btw, the turbo multiplier is x21, unless you are only using 1 core, then it's x22 on one core if at stock speeds.
 

bigbang

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what by stander and I are trying to say is, working with the turbo boost, is going to have more complications in finding a stable setup because of the fact that the increased ratio affects the signal between cpu and ram in a nonlinear fourier space, so just giving out numbers will probably not solve the issue. it will take a lot of testing at the same clock to give u a stable turbo boost, and even then it might only be stable 95% of the time, since the fourier transform is a periodic module.
 


This is directly from the guide: 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.

Btw, x21 is the turbo multiplier, except in the case mentioned above. x22 is the multiplier ONLY at stock speeds while using 1 core.
 

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