How to set up GTL Ref Values for 45nm & 65nm

[spoof]

Lower your VTT and increase CPU voltage, should make difference.

A

It should, but it does not. Actually, it's Prime-stable for more than 3 hours, at this time i'm running it at 1.4065, BIOS says it's 1.352, OCCT says 1.36. If i lower it or increase it, it just affect the stability in Prime(actually, 1.4125 is the max, what i was trying). And again, which value is real - 1.4VTT BIOS set, or BIOS Hardware Monitoring and Everest - 1.34. And can i lower VTT and set 67x for GTLREF or it's too much?

[CryptiK]

how do i set GTL for a 65nm dual core? when i stress test both core 0 and 1, it consistently fails on core 1 first. in my M2F bios, it shows the following equation for GTL:

core-0: vtt x .635 + item
core-1: vtt x .667 + item

what i don't understand is that since it's a 65nm chip, then shouldn't i change the "Y" value for core-0 to match the .667? in my case, why is core-1 less stable? then do i need to change my core-0 or core-1? my vtt is at 1.37v, so i should set the "Y" value of core-0 should be about +43mV correct?

Being a Q6600, a GTL Ref of around 0.65x should give you optimal results. So reduce the 0.667x and increase the 0.635x.

Sitting on a Rampage Extreme and a E8600. The board has CPU GTL Ref 0,1,2,3

VVT = 1.20

So i calcute this

1.20 x 0.635 = 0,762
1.20 x 0.667 = 0,800

0,762 - 0,800 = 0,038

= ~ -40mV

I´m i on the right track ?

CPU GTL Ref 0 = Auto
CPU GTL Ref 1 = -40mV
CPU GTL Ref 2 = Auto
CPU GTL Ref 3 = -40mV

How can i calculate NB GTL ?

Yep thats fine. I have given some other alternative settings like +10/-30/+10/-30 and others in a previous post so try some other combos too. When I use Vtt ~1.20v my e8400 likes +50/+10/+50/+10 for the GTL's.

I have the MSI P45 Diamond and I cant get it to post at 400FSB. Im using a Q9550.
My BIOS looks like this:
*snip*
I can adjust the CPU GTL and the MCH GTL in small steps and If I have understood this right, I should let it be somewhere between 0,8 and 1,0? I don't have to do the calculation.
I have tried to just adjust the MCH GTL to 0,6369v and then left everything else on auto, that works ok up until about 375FSB. If I want it to boot at 380 I have to change that setting to auto and put a very high vMCH and VTT.
Any ideas what I should set the CPU GTL and MHC GTL to make it boot at 400FSB if that's even possible? I know it's not an extreme motherboard and its a quad, but 400FSB? I'm looking for bench-settings.

Perhaps setting the appropriate vcore and Vtt, (probably around 1.4vcore & 1.3 - 1.4v Vtt for 4GHz) and using around 1.3 - 1.4 vNB (vMCH) then setting GTL's to around 0.75 - 0.85v should work. Leave your NB (MCH) GTL Ref around the 0.64x Vtt mark.

Which GTL Ref adjustment should I use on my M2F with q6600?
+ or - ond how much mV on 0,1,2,3 ?

This depends on your Vtt, have a read through the thread and get an understanding of the relationship between the GTL's and Vtt (vFSB).

I'm with P5E-Deluxe@Rampage Formula. When i set 1.42VTT in BIOS, Everest shows, that VTT is 1.34. Which one should i trust - sensoar reading or bios setup? My GTLREF setting is 65x.

neither can really be trusted 100%, but either setting is below the absolute max intel spec. You can always check with a DMM look for the measure points or ask in your mobo thread for someone to show you where to measure it.

It should, but it does not. Actually, it's Prime-stable for more than 3 hours, at this time i'm running it at 1.4065, BIOS says it's 1.352, OCCT says 1.36. If i lower it or increase it, it just affect the stability in Prime(actually, 1.4125 is the max, what i was trying). And again, which value is real - 1.4VTT BIOS set, or BIOS Hardware Monitoring and Everest - 1.34. And can i lower VTT and set 67x for GTLREF or it's too much?

Sounds like you have one or more voltage settings too low, or your GTL's arent set up. However crashing/locking up on idle is usually only affecting people using LLC and from your vdrop it appears you are not using it. Make sure your vNB (vMCH) is set high enough to keep it stable, and make sure your ram is stable also.

If you cant find what setting is responsible for the instability, drop the speed until it is stable and work up from there again.

Also running 0.67x GTL ref with ~1.34 Vtt is fine you just need to keep your Vref under ~1.0v as the max. that setting would give you 0.897v which is fine.

[OC4/3]

@CrystiK

Got it, checked my bios now and it seems like im only limited to 1.2375VTT

I would assume that playing around with the VTT and GTLREF provides no risk or what so ever?

EDIT:

Right now ill try vtt at 1.2375 and GTLREF at 67% in hopes that i can run at lower vcore, trying 1.315vcore under prime95SmallFTT.

See if more vmch unlock up to 1.4vtt?

[spoof]

neither can really be trusted 100%, but either setting is below the absolute max intel spec. You can always check with a DMM look for the measure points or ask in your mobo thread for someone to show you where to measure it.



Sounds like you have one or more voltage settings too low, or your GTL's arent set up. However crashing/locking up on idle is usually only affecting people using LLC and from your vdrop it appears you are not using it. Make sure your vNB (vMCH) is set high enough to keep it stable, and make sure your ram is stable also.

If you cant find what setting is responsible for the instability, drop the speed until it is stable and work up from there again.

Also running 0.67x GTL ref with ~1.34 Vtt is fine you just need to keep your Vref under ~1.0v as the max. that setting would give you 0.897v which is fine.

First of all, i'm extremly thankfull, that you are trying to help!
So, here is what i've done so far:
vNB is set to 1.51 with GTLREF Auto. Increasing it to 1.53 don't solve the problem.
CPU voltage is set to 1.4065 as i sayd, but i figured out, that i just affect prime stability.
I've tried CPU PLL values from 1.52 to 1.66, no change at all, may be with lower setting it freezes "slower".
FSB Termination (or VTT) - from 1.20 to 1.42(right now), with 1.42 it's still working, but even with lower value sometimes it works for days before lockup.
This is all i have for the CPU.
My memory is PC8800 (1100Mhz) and while testing the cpu i'm using it at 1:1 - so no problem here.

The one think, that i noticed - 450x8.5 with vCPU 1.3725 1.5 CPU PLL and 1.2VTT i have now lockups. With same voltages 455x8.5 it freezes, so i need to increase VTT. So i think this is the critical voltage, but i'm still no much into it, safe range and etc. GTLREF set from 59x to 65x doesn't help too.

Sorry for my english.

:edit: Just froze at 1.42VTT too Trying 1.36VTT with 0.67x GTLREF

[CryptiK]

Hmm ok. Try using 1.3725 vcore, 1.22 Vtt, 0.67x GTL Ref, 1.55 vNB at 455 FSB. Also try advancing you ram skews to around 250 - 300ps if you have them.

Also, can you raise GTL Ref above 0.67x? I have seen some guys with C0 stepping 9550's needing around the 0.68x - 0.73x mark for 4GHz, but some also need around 1.42v load for stability at 4GHz.

[truehighroller]

Hmm ok. Try using 1.3725 vcore, 1.22 Vtt, 0.67x GTL Ref, 1.55 vNB at 455 FSB. Also try advancing you ram skews to around 250 - 300ps if you have them.

Also, can you raise GTL Ref above 0.67x? I have seen some guys with C0 stepping 9550's needing around the 0.68x - 0.73x mark for 4GHz, but some also need around 1.42v load for stability at 4GHz.

Just to add my . Looking at what he said about the whole days before locking up.. Mine does this if I have my NBv set to high. I can run it fine and then wam it will do something stupid like never boot to where I have to reset it to get it to boot. If I have my voltage on my nb set just right it never happens. My example I am refering to is in better detail,,, If I set my NBV to 1.34 this issue will happen.. If I leave it set to what I have it set to right now, 1.3v it never does this.. My .

[spoof]

I'll try this too, it isn't impomssible. What about GTLREF on NB? Is there something to be aware of? I'm using it now with vNB 1.51 and 57x GTLREF.

[truehighroller]

I'll try this too, it isn't impomssible. What about GTLREF on NB? Is there something to be aware of? I'm using it now with vNB 1.51 and 57x GTLREF.

I would try backing it down to say 1.34 and leave the gtl ref for it "nb" set to auto and see if you can boot with it set like this.

[spoof]

I would try backing it down to say 1.34 and leave the gtl ref for it "nb" set to auto and see if you can boot with it set like this.

Yep, this would be the next step. Now - 1.4125 vCPU, 1.50 CPU PLL, 1.38VTT, 67x GTLREF, vNB 1.51 with 57x GTLREF, LLC disable. And skews set to normal for both channels.

[Big Lar]

For the NB GTL Ref, this is how it works out for me up to about 486fsb with my chip and board:

VTT X CPU GTL Ref = TREF divided by my NB Voltage = NB GTL.

So:
1.30vtt x 0.675 CPU/GTL = 0.8775 TREF Divided by 1.36 NB Voltage = 0.64522 = NB GTL of .645 to .650.

This has worked all the way up to 486fsb for me, testing 488fsb closer now but it seems it is doing OK there as well. Just thought I'd throw that in the mix.

Larry

[truehighroller]

Yep, this would be the next step. Now - 1.4125 vCPU, 1.50 CPU PLL, 1.38VTT, 67x GTLREF, vNB 1.51 with 57x GTLREF, LLC disable. And skews set to normal for both channels.

I'm sorry, I was thinking you are on a P5Q Deluxe... I looked at your signature again and was like oops... Our boards are different Larry. My guess is that you aren't to bad off at 1.5NBv considering it is x48. Long busy day at work, sorry for the confusion.

[spoof]

I'm sorry, I was thinking you are on a P5Q Deluxe... I looked at your signature again and was like oops... Our boards are different Larry. My guess is that you aren't to bad off at 1.5NBv considering it is x48. Long busy day at work, sorry for the confusion.

You mean, 1.5v isn't very high? Just tried lower the vNB to 1.39 (or 1.40, dunno) i it froze just after logon. So, could more vNB fix the problem? It's easy, i'll put it under water, so no worry about t*, but will fix it?

[davidk21770]

With a quad and 4x2gb of memory you'll need lots of NB. I've been told that 1.6v is "safe" as long as you control the temps.
I'm testing 1.53 right now trying to stabilize 442x9 and I only have 2x2GB of memory.
(Luckily, this MB has an awesome heatsink on the NB and PWM chips.)

[truehighroller]

You mean, 1.5v isn't very high? Just tried lower the vNB to 1.39 (or 1.40, dunno) i it froze just after logon. So, could more vNB fix the problem? It's easy, i'll put it under water, so no worry about t*, but will fix it?

I don't know. I think that will be fine. My experties are with p45. Can some one chime in for him on this one. I think you will be fine with a little more let's see if I'm right or not.

[Big Lar]

I had the DFI X48 LP LT DDR2 board, I ran 1.56v on the NB daily, I think even 1.6v is fine on that chipset as long as temps are ok.

Larry

[mikeyakame]

with the x48 as long as u keep nb temps sane ( < 50c ) you can push all the voltage into it u want, but 1.6-1.65v and it becomes pretty frivolous since it just makes more heat and little gain. i ran 1.59v on mine air cooled for ages. I run 1.49v now cause tight Performance Level on top of highish FSB freq isn't very healthy for day to day use, generally ends up with memory errors or random software faults (ie windows search randomly couldnt find files on my system). I use PL 7 with 466MHz fsb and 1.49v vNB and 0.63x NB GTLREF and thats what mine likes at this freq.

um my vtt should be 1.38v in bios which gives an output voltage of 1.41v atthe sensor.

[Brama]

um my vtt should be 1.38v in bios which gives an output voltage of 1.41v atthe sensor.

Very strange........normally Rampage Formula sets the VTT 0.06-0.08 V down the BIOS programmed value.

Mine, for example, with 1.40 V programmed in BIOS, read 1.32 from the sensor...

[CryptiK]

Make sure you do a cmos clear after flashing the bios. With my asus boards if i flash and dont clear cmos afterwards the real voltages change even when you use the same setting in bios as before. If you clear cmos, the voltage goes back to what it used to be for that setting.

[truehighroller]

Yeah the board is quarky that is for sure. It doesn weird things with latencies to if you don't really clear the cmos good after flashing.

[Xello]

I was wondering, is GTLref still playing as large a roll in i7 as it sometimes does in core 2? Haven't come across much info on that yet myself.

[mikeyakame]

Very strange........normally Rampage Formula sets the VTT 0.06-0.08 V down the BIOS programmed value.

Mine, for example, with 1.40 V programmed in BIOS, read 1.32 from the sensor...

i use loadline calibration perhaps that is why?

[CryptiK]

I thought that LLC was only for VCC and not for Vtt or other voltages? It makes no difference to voltages other than VCC on my board.

Asus boards do seem all over the place these days though, I think their QC has all but disappeared. I have seen many times now people setting the same voltages in bios and getting very different real voltage readings. Every time I flashed my P5Q-Deluxe I would get different real voltages when I set the same voltages in bios as I had before the flash.

I think they are cutting so many corners during manufacture there is no consistency anymore.

[LuckySevn]

ideal nb gtlref for standard Intel values is 0.666x vTT, but there is an extra value for the NB called FSB_SWING which is 0.25x vTT nominal, this is set by the manufacturer and it determines the distance for logical 0 / 1 from gtl ref voltage. it's the swing distance for a switched voltage. It may be that this is based off a divider from the GTLREF NB voltage which has already been reduced by a set of 1% resistors, it would make sense to do something along these lines as too high a vTT would cause too large swing between ground and power, perhaps thats the reason why we use smaller NB GTLREF multipliers or values.

Hi Mike, thank you for all the information thus far, I've finally gained some better understanding on VTT and GTL. All other articles I've come across are either vague or utterly confusing.

So based on what I've read here, my settings should be:

CPU vCore: 1.475v
CPU PLL: 1.58v
CPU GTL Ref: 1 / 1.475 = x0.67
NB: 1.49v
VTT: 1.48v
NB GTL: 0.80 / 1.48 = x0.57

Am I correct? Thanks!

[gravimag]

i have queastion about GTL settings on maximus II formula. In bios there is nothing like x0.667 or x0.635 wit GTL's but mV, can somebody help me to find our how to adjust this settings?

[mikeyakame]

Hi Mike, thank you for all the information thus far, I've finally gained some better understanding on VTT and GTL. All other articles I've come across are either vague or utterly confusing.

So based on what I've read here, my settings should be:

CPU vCore: 1.475v
CPU PLL: 1.58v
CPU GTL Ref: 1 / 1.475 = x0.67
NB: 1.49v
VTT: 1.48v
NB GTL: 0.80 / 1.48 = x0.57

Am I correct? Thanks!

try 1.46/1.48v vtt with 0.63 - 0.65x for cpu, and nb try 0.61-0.63x
you'll just have to find the sweet spot for your fsb frequency and your particular board.

normally i find if i use the right vtt voltage, then i can just set 0.65x for cpu and 0.63x for nb!