Vdd question (Epox 8RDA+)

[Bravo]

Hello all.

Let me fill you in on some background information.

I picked up an AIUGB stepping 2400. When coupled with my watercooling setup (Cathar White Water CPU block, Ehiem 1048, High Quality Stubby Arse heatercore/shroud) and system (Epox 8RDA+ (C27), 256mb PC-3200 TwinMOS, Antec 550watt PSU) i was able to squeeze 2482 (12x 205) out of it at 2.025v prime95 stable. I have since gotten a classic model vapochill. Summer here has killed most of the high clock speeds, it was basically 25 USD + my old watersetup to go to this classic unit, and i couldnt refuse given it would hold the CPU temperature below ambient no matter what the air temperature was anyway.

Going on, i got the classic unit vapo, and while setting up my system to recieve it, i cracked the processor not on the corners, but on the lower ridge of the CPU die. I set it up anyway, plugged it in, and got a post. I was able to clock the processor to 2400mhz @ 1.85v, and running a higher voltage made no difference to the CPU clock speed. Yesterday/lastnight, i left Sandra doing CPU Arithmetic via the Burn-in Wizard, with the CPU set to 10x 200 @ 2.075v. I woke up this morning, attempted to clock higher, and found it made no difference.

I just plugged in my SMD grabber, with the Vdd dialed to 1.75v. I am now running 2482 (11.5x 215) @ 1.975v. My processor was unable to boot, let alone prime in windows at this speed beforehand.

Can the Vdd affect CPU stability/overclocking?

[Stepper]

I like the 2400/8RDA combo...

[Stepper]

Originally posted by Stepper
I like the 2400/8RDA combo...

I haven't done any mods...cause I can't see well enough to do em...

[N8]

Dang, I take it those screenshots are clear to you stepper? Blury as hell to me, lol

[KingInge2000]

Originally posted by Stepper
I like the 2400/8RDA combo...

@ what vcore are u running?

[Stepper]

Originally posted by N8
Dang, I take it those screenshots are clear to you stepper? Blury as hell to me, lol

Well...when I hit the print screen button and then paste the shot in paint...I get a 2.5mb bitmap...which I can't post...so what U see is the result of reducing the size and changin it to a jpeg...if U'd like...I can send U the 2.5mb file...

[Stepper]

Originally posted by KingInge2000
@ what vcore are u running?

2.1...I'd use the 2.2...but I've already hosed 2 bios chips doing that...I could get more outta it with the 2.2 vcore...but...what for...

[N8]

Nawww...I just thought you were using a windows accessibility option or something to counter your vision as you mentioned it wasn't so good. Just thought the pic kinda looked like when I look thru my wife's glasses

[Stepper]

^5...np...I am blind as a bat...blind in one eye...can't see out the other

[BrainStorm]

Stepper, very nice . How are you getting the 223 FSB without a voltage mod??? I haven't seen anyone near that high without it

[Stepper]

Originally posted by BrainStorm
Stepper, very nice . How are you getting the 223 FSB without a voltage mod??? I haven't seen anyone near that high without it

Ya gotta understand...I don't run FRANK at those speeds...I jus set him uP at optimal settings jus to see "IF" he'll run there...this is a 'BIGG RICHARD' thing...an I've got really BIGG Feet...knowhatimsayin...a lot has to do with how I run Frank's hd...so as not to get corrupt files...runnin voltage that'll for sure roast the bios...turn off all the background BS...and hours and hours of twistin Frank's knobs...which he really doesn't like...I usually run Frank at jus ova 200fsb so as to be able to use the 3200's 400mgz...U know I've blown Frank's brains out twice...one thing that I'm not sure about though is...I got this chip from a dude that used it in a Prometeia ( READ FROZEN! ) so jus maybe this chip is a tad different from the run of the mill chips...who knows...

[CodeRed]

Bravo,
If someone could answer the following questions then maybe it would shed some light on why your CPU can go faster when the Vdd is higher (even with a higher multiplier and lower FSB .. clarified via ICQ).

1. The CPU uses several voltages not just Vcore. So what parts of the CPU use Vcore only?
2. I suspect the ATGL tranceivers (FSB I/O pins) use a different voltage than Vcore as they are bipolar transistors not CMOS. So does Vdd affect the FSB I/O voltages?
3. Does the PLL run at Vcore or some derivative of Vdd?


Can anyone with some detailed info on the XP or NForce2 shed some light on this?

Cheers
CodeRed

[Bravo]

The plot thickens.

I dialed the Vdd to 1.80v, and Vcore up to 2.15v, and left the CPU priming/using Sandra Burn in (CPU/Mem @ 12x 200). Got up this morning, and she is now prime95 stable @ 2499 @ 1.975v.

My 5/12/3.3v lines are looking horrible however:
12v = 11.49v
5v = 4.73v
3.3v = 2.86v

What does the 3.3v line do? Im worried about it being so low.

[CodeRed]

Bravo,
starting to get a few ideas. The XP model 8 has 3 voltages fed to it

3.3V --> dont know what part of the CPU this feeds
VCCA 2.5V ---> PLL & I/O
VCORE 1.65V ---> guts of the CPU

Maybe VCCA is controlled by or derived from the chipset voltage????

[BrainStorm]

Originally posted by Bravo
The plot thickens.

I dialed the Vdd to 1.80v, and Vcore up to 2.15v, and left the CPU priming/using Sandra Burn in (CPU/Mem @ 12x 200). Got up this morning, and she is now prime95 stable @ 2499 @ 1.975v.

My 5/12/3.3v lines are looking horrible however:
12v = 11.49v
5v = 4.73v
3.3v = 2.86v

What does the 3.3v line do? Im worried about it being so low.

Bravo, if you have a nForce2 board, the 2.86 reading is probably your voltage to your memory, rather than the true 3.3 volt rail. I believe that is a problem inherent to nForce2 boards (at least if you are reading it anywhere in Windows (e.g., with MBM).

[BrainStorm]

Originally posted by Stepper
Ya gotta understand...I don't run FRANK at those speeds...I jus set him uP at optimal settings jus to see "IF" he'll run there...this is a 'BIGG RICHARD' thing...an I've got really BIGG Feet...knowhatimsayin...a lot has to do with how I run Frank's hd...so as not to get corrupt files...runnin voltage that'll for sure roast the bios...turn off all the background BS...and hours and hours of twistin Frank's knobs...which he really doesn't like...I usually run Frank at jus ova 200fsb so as to be able to use the 3200's 400mgz...U know I've blown Frank's brains out twice...one thing that I'm not sure about though is...I got this chip from a dude that used it in a Prometeia ( READ FROZEN! ) so jus maybe this chip is a tad different from the run of the mill chips...who knows...

Stepper, even for a BONZAI benchmark run, 223 without vdd mode is incredible! I doubt I could get anywhere even close (but I need to do some work on cooling the NB and SB!)

[Bravo]

Ar good.