VTT voltage/GTL settings - guide needed

[graysky]

Just put a new system together on a DFI LT P35-T2R based system (X3360 CPU). Anyway, I found this but it's not really source of info... can someone point me to a description of how to o/c using the VTT Voltage and GTL settings? My old P5B Del didn't have these options.

 

[LittleNemoNES]

You mean this?:

http://www.anandtech.com/mb/showdoc.aspx?i=3129&p=12

I thought it was pretty useful.

 

[bryanW1995]

link is broken.

rubicon and aigo both have dfi mobos, something tells me that they know a thing or two and could help you

 

[The-Noid]

FYI not to sound like an ass, but if you mess with these and don't know what you are doing you are going to ruin your cpu.

Nothing and I mean nothing kills these 45nm faster than GTL and VTT voltages. That is why ASUS is limiting them in their new mobos that have a 45nm installed. For the minor benefit you get of 15-20 mhz of FSB you are putting your hardware in major danger, and this comes from a guy whose hardware is in danger at all times.

 

[bryanW1995]

<---checking out vtt and gtlref settings on ip35 pro...um...

 

[graysky]

Thanks for the discussion, all. Yoxxy makes a good point about leaving it disabled. I'm only running it @ 8.5x400 @ 1.13750v (currently p95'ing+x264.exe stressing it) with GTL disabled.

 

[LittleNemoNES]

Originally posted by: Yoxxy
FYI not to sound like an ass, but if you mess with these and don't know what you are doing you are going to ruin your cpu.

Nothing and I mean nothing kills these 45nm faster than GTL and VTT voltages. That is why ASUS is limiting them in their new mobos that have a 45nm installed. For the minor benefit you get of 15-20 mhz of FSB you are putting your hardware in major danger, and this comes from a guy whose hardware is in danger at all times.

How else would be learn if not by trying?(any of us, really)

Hell, I didn't know WTF GTL was when I bought my x48T2R and x3350. I read up on some articles on xtremesystems and the anandtech one I linked to earlier and that was enough to get me going.

Reading carefully is the key to implementing GTL correctly.
Besides, the default settings can sometimes be a little higher than normal...

Peace

 

[graysky]

Is there a util that can report the GTL values the BIOS selects when on auto mode?

 

[graysky]

Hmm... so GTL is defined as 2/3 of VTT (termination voltage) by default... what is the effect on hardware by keeping a lower VTT but a higher GTL? In other words, don't keep the "default" 66.67 % ratio. Bump it up to 70-80 % for example.

1.2 V on the VTT and say 95 on the GTL (95/120 = 79.2 %). Is this bad for the hardware?

 

[Syzygies]

Of related interest, here's a link overclocking the DFI LT P35-T2R to DDR2 1100 MHz with 8GB of ram:

http://csd.dficlub.org/forum/showthread.php?t=4684

I'm not seeing your answer in his screen shots, but you could post there for more info?

 

[bryanW1995]

that's odd, my ip35pro is 1.20vtt by default and 67% gtlref by default. are you saying gtl is .8v by default?

 

[Winterpool]

My buddy couldn't get his Q6600 stable at 3 GHz, 333 FSB, default voltage. Then he increased the GTLref on his IP35-E from, I believe, 63 to 65 per cent, didn't touch anything else. Now it's perfectly fine. I wish I understood why. Normally I'd be with Yoxxy and not touch acronyms I don't know much about. On the other hand bumping GTLref 2 per cent seems less drastic than increasing cpu voltage...

 

[dmens]

Originally posted by: Winterpool
My buddy couldn't get his Q6600 stable at 3 GHz, 333 FSB, default voltage. Then he increased the GTLref on his IP35-E from, I believe, 63 to 65 per cent, didn't touch anything else. Now it's perfectly fine. I wish I understood why. Normally I'd be with Yoxxy and not touch acronyms I don't know much about. On the other hand bumping GTLref 2 per cent seems less drastic than increasing cpu voltage...

http://www.thetechrepository.com/showthread.php?t=87

I have not dealt with FSB ringing or I/O in general so I cannot give any advice, but small tweaks on the reference voltage can cover up functional holes caused by out-of-spec operation. When the bus voltage is increased, the compensation resistor needs to be adjusted to match. But hell if I know how to do the math.

 

[Syzygies]

Originally posted by: dmens
http://www.thetechrepository.com/showthread.php?t=87

I have not dealt with FSB ringing or I/O in general so I cannot give any advice, but small tweaks on the reference voltage can cover up functional holes caused by out-of-spec operation. When the bus voltage is increased, the compensation resistor needs to be adjusted to match. But hell if I know how to do the math.

That's none other than our own Kris Boughton, before he got picked up by AnandTech. Clearly, here a good editor got him to write for a broader audience, and spell out "this is good, that is bad". Earlier in that same forum is a precursor to his Vdroop recommendations here, so roundly ignored. We need an animated Homer emoticon, "Vdroop - You say that like it's a bad thing", and his message might get out. I see this link also being ignored.

Ironically, I have that "Bad Axe 2" board in my first build, and there's a more basic mod it needs. I tried overclocking it exactly once, recently, and it sure looked like I had bricked it until I realized there's a jumper one moves to reset the BIOS. You've got to be kidding, right? I guess Gigabyte has spoiled me, people actually put up with this? In any case, my first reaction was to wire a jumper switch, and sure enough, a google search finds others doing the same.