BlackOps/Avenger: GTL Ref Table

[saaya]

im burried in emails and work, but heres a quick headsup for you all

Theoretical CPU GTL steps
BIOS setting VTT*
31 0.740
30 0.736
29 0.732
28 0.728
27 0.724
26 0.720
25 0.717
24 0.713
23 0.709
22 0.706
21 0.702
20 0.699
19 0.695
18 0.692
17 0.688
16 0.685
15 0.682
14 0.678
13 0.675
12 0.672
11 0.668
10 0.665
9 0.662
8 0.659
7 0.656
6 0.653
5 0.650
4 0.647
3 0.644
2 0.641
1 0.638

default 0.635

-1 0.632
-2 0.629
-3 0.626
-4 0.624
-5 0.621
-6 0.618
-7 0.615
-8 0.613
-9 0.610
-10 0.607
-11 0.605
-12 0.602
-13 0.599
-14 0.597
-15 0.594
-16 0.592
-17 0.589
-18 0.587
-19 0.584
-20 0.582
-21 0.579
-22 0.577
-23 0.575
-24 0.572
-25 0.570
-26 0.568
-27 0.565
-28 0.563
-29 0.561
-30 0.558
-31 0.556





meassured CPU GTL steps with 8600:
31 0.787
30 0.783
29 0.778
28 0.773
27 0.768
26 0.763
25 0.759
24 0.754
23 0.749
22 0.744
21 0.739
20 0.735
19 0.730
18 0.725
17 0.720
16 0.715
15 0.711
14 0.706
13 0.701
12 0.696
11 0.691
10 0.687
9 0.682
8 0.677
7 0.672
6 0.667
5 0.663
4 0.658
3 0.653
2 0.648
1 0.643

default 0.639

-1 0.634
-2 0.629
-3 0.624
-4 0.619
-5 0.615
-6 0.610
-7 0.605
-8 0.600
-9 0.595
-10 0.591
-11 0.586
-12 0.581
-13 0.576
-14 0.571
-15 0.567
-16 0.562
-17 0.557
-18 0.552
-19 0.547
-20 0.543
-21 0.538
-22 0.533
-23 0.528
-24 0.523
-25 0.519
-26 0.514
-27 0.509
-28 0.504
-29 0.499
-30 0.495
-31 0.490


Ill pass this on to the BIOS engineer and the future BIOSes should have the direct table and no more "+1" or "-4" stuff

If theres anything you wanna know please let me know!
Im quite busy since i just got back from a 3 weeks business trip
so it might take a few days before i can reply

[HDCHOPPER]

exellent man exellent !! this is the kind if info that really helps

[SF3D]

Finally! I was saying this from the start, but it didn't make any difference

[yiancar]

Tnx guys this REALLLY helps out

[negev]

Could someone explain to the clueless person what this means?

I'm guessing those are voltage adjustments, does that mean that VTT GTL +31 means an extra 0.740v?

[TheGanG]

Actually hate +/-1,2,3 stuff... Now that new values are comparable with other mobos' GTL Ref. voltages, Thanks...

New BIOS Update on these days?

[Xello]

Could someone explain to the clueless person what this means?

I'm guessing those are voltage adjustments, does that mean that VTT GTL +31 means an extra 0.740v?

You're not actually changing any voltages with the gtl setting, it's a reference value that the motherboard uses to determine if a signal is 'high' or 'low' (1 or 0).

[negev]

I'm guessing you need an oscilloscope to actually work this out properly..

[Xello]

Well i tested out GTL refs with this board extensively for my QX9650 (see other thread for results) and the one thing i learned is just to go with what everyone else is using (+10, +5, +10, +10 for the 9650), as after 2 weeks or so of testing this is what i ended up on, and the instability i was having i narrowed down to other settings.

The NB GTL is a different story though, may take experimentation.

When i asked Raja from Anandtech about possible variations of the cpu gtl's he said this:

"The GTL adjustments I typed out to you [+10 +5 +10 +10] are representative of close to ~67% of VTT. Which is pretty much what the 45nm QX9650's prefer as a rule. The scale adjustments on the black ops seem to fall around the 15mv range, so anything away from these values is unlikely to be a whole lot better for most people. While there is variance in substrates across batches, it's unlikely that the variance is so large that GTL's on 2 same model processors should be out by more than 1%. "

[negev]

Yeah I am currently using 10-5-10-10 on my Q9450 and it's stable at 3.33, haven't pushed any higher with this new ram yet. Is what you said likely to also apply to the whole 45nm product range? AFAIK 9450 and 9650 are basically the same just binned differently and one has an unlocked multiplier no?

[Slovnaft]

ooh this is useful
i've never toyed with gtlrefs on my proc cos i didnt know what was sstanddard

[Xello]

Yeah I am currently using 10-5-10-10 on my Q9450 and it's stable at 3.33, haven't pushed any higher with this new ram yet. Is what you said likely to also apply to the whole 45nm product range? AFAIK 9450 and 9650 are basically the same just binned differently and one has an unlocked multiplier no?

Should be, yup, as it's the process that determines the GTL ranges (and dual/quad)

[saaya]

I'm guessing you need an oscilloscope to actually work this out properly..

no you can meassure it with a DMM actually
you dont actually change a voltage as in a supply voltage, but there is a GTL voltage which is used as reference to check if a signal on the fsb should be interpreted as a 0 or a 1, and this ref voltage can be meassured.

Ill check where the measuring spots are on different boards and will check how accurate the bios settings are.

so do you guys want the actual reference voltage as a setting or do you prefer the 0.67x vtt setting that asus and others are using?

as for what gtl setting works best, i think even among 9650s theres a difference from cpu to cpu, intel reworked their 45nm process a couple of times and there should be a difference between c0 and c1 stepping as well... but yeah, the settings raja recommends should work well for most 9650s or be close to the best setting

if your reading this, thanks again for the good work raja

[HDCHOPPER]

actual reference voltage would be my fav it leaves no guessing or magic questions in my little brain

[jolliffee]

Good Progress, any chance the BIOS guys could parse the actual value next to the auto settings so say, we could see what the actual BIOS settings for memory timings next to the auto.

[saaya]

Good Progress, any chance the BIOS guys could parse the actual value next to the auto settings so say, we could see what the actual BIOS settings for memory timings next to the auto.

yes, thats possible, but it takes a LOT of work according to our bios engineers, so they are focussing on memory/chipset/fsb tweaking for now. its def on the list of things we want to add tho

[saaya]

updated the first post and added a table i created by meassuring GTL REF voltages, so this table should be more accurate.
ill check with a quadcore tomorrow to see if there are any differences

i checked with vtt 1.1v and 1.5v and the ratios are identical and dont change at all like on some other boards.
really solid and reliable GTL REF ratio tuning

[Wotcher]

I'm pretty new to this (GTL ref tweaking) so bear with me please, I'm having a little difficulty relating the math to the m/board settings options

Black Ops (500*8) Bios G30 and an E8600 (Q820A599)@4.0GHz, 1.2375V bios



Using this formula: Vtt*0.667+Y = Vtt*0.635

Vtt is 1.2

1.2*0.667+Y = 1.2*0.635

0.8004+Y = 0.762

Y= 0.762 - 0.8004 = -0.0384

so 0.667 - 0.0384 = 0.6386 or Default in the above table (second one)

amirite?



EDIT: Also, did I read somewhere that although the bios/Aegis panel is reporting 1.2V for the Vtt it is actually 1.1V? (45nm dual core)

so the above should read

1.1*0.667+Y = 1.1*0.635

0.7337+Y = 0.6985

Y = 0.6985-0.7337

Y = -0.0352

so 0.667-0.0352 = 0.6318 or -1 in the above table (second one)

[saaya]

hey wotcher

sorry, dont get why you include Y in your calculations?
actual vtt times ratio = actual gtl ref voltage
and yes, actual vtt for 45nm cpus is .1v lower than the bios shows with G30

[Wotcher]

Hey saaya, I was confused to start with and now I'm not so sure

I had the whole thing back to front I think, my setting should be +7 by my latest understanding, as I said I'm fairly new to GTL ref voltage tweaking but I believe I'm learning.



dropped Vtt back to 1.2V bios (1.1 actual)

1.1x0.667 = 0.7337

1.1*0.635 = 0.6985

0.7337 - 0.6985 = 0.0352

0.635 + 0.0352 = 0.6702

0.6702 = +7 (or there abouts)

I'll give this a run tonight when I get home from work.

I appreciate you taking the time to help me.

[Sailindawg]

Wotcher,

That formula was taken from the sticky thread in the Intel forum. That formula makes sense if you have that ASUS board or the BIOS adjusts GTL ref values by giving BIOS entries in mVolts only. That formula helps adjust VTT either up or down of the reference value of 0.67x of VTT or 0.635x of VTT.

What Foxconn did makes more sense. They assigned the various voltages for GTL 0.67x ref values a whole number that's dependent upon the VTT voltage used. All you need to do is simply take 0.667 of a given VTT voltage and look up the corresponding BIOS value according to Saaya's chart. The entire thread is here.

Saaya created an Xcel spread sheet where you put your VTT of choice in the top entry and the associated values for the BIOS numbers are updated. Take your previously calculated 0.67x voltage and look up the associated whole number quite directly. I usually use a range of GTL ref values until I get one that works. Saaya's chart helps eliminate the guess work when adjusting VTT voltages and GTL ref values.

[Wotcher]

Thanks for that, I saw both thread and chart earlier and that is what tempted me to try tweaking the GTL ref value.

Then I saw the thread here that used the above formula and that is where it turned to turd I think

Using the chart it appears I should be around +9, +10, +11 to get my 0.7337 at 1.1 Vtt


I'll get 4.5GHz stable in the end

[saaya]

thx Sailindawg
glad you got it all figured out in the end wotcher

[Vatos_locos]

may i ask where do we measure the GTL on the avenger :p ?

[OdinEidolon]

good to know, but when will avenger be avaiable in EU?