Odd Trouble with Shuttle an35n Ultra and XP 1700

[GreatDaleness]

Just got a new Shuttle AN35N Ultra MB, sk7, AS Ceramique, and thermaltake 80MM fan (the one with 75 CFM at max speed).   I am using my old XP 1700 and seeing how far it will go.  I have 3 80MM case fans, and a 300W Antec power supply.  I can OC to 166 FSB by 11 and remain rock steady with only a 3 degree temp rise (from 35C to 38C), but if I attempt to raise the multiplier to 11.5 or the FSB to 170 (memory is locked at 166) she won't boot.  Worse, the BIOS won't load.  I have to short out the battery.  When I do get a post, the hard drive doesn't work right.  I get a screen full of numbers or a screen that tells me the system files can't be found. This is all very odd, especially since I taped the fan's thermometer to the sk7, and the fan never raises above minimum.   I am using the latest BIOS and drivers, a fresh install of windows, etc etc etc.  Anyone have any idea what the problem could be?  Power supply maybe?  My system specs are below.
 
Shutle An35N
3 antec smartfan 80 MM
1 Thermaltake smartcasefan
CDRW
dvdRom
6GB 5400 HD
40 GB Seagate HD
Audigy 2
9500pro (not overclocked)

 

[Soulkeeper]

it might be yur psu
300watts is pushing it
what are your voltage rails looking like as you raise the mult to your highest stable speed ?

 

[phpdog]

what type and how much RAM are you using ?

 

[GreatDaleness]

Voltages are a little off 5-10% except for -5 which is at 3.5.
The memory is 2X 256 Cruical PC 2700, and the speed on the memory I have locked at the highest level it will go (166 Cas 2.5 3 3 5), so it is not the problem. Scanning these voltages, I guess that is the problem. I just find it odd that it kicks out right at 166 FSB. I can go 13.5X133 or 11X166, remain cool and error free, yet 2% more speed leads not to slight errors, but a complete failure. No post, no BIOS, the only option is to clear the BIOS and start over.

 

[GreatDaleness]

Ok, I took out the extra hard disk and cdrom and the voltages didn't change, so this doesn't seem to be a power supply question. I have further researched and found out what IS the problem, but I don't understand it. Going from 166X 11 to 166X11.5 (and changing NOTHING else) I get MEMTEST failures. More than 5000 on test one alone. I didn't change the memory settings at all! 166X11 perfect memtest for 24 hours. 166X11.5 utter failure of memtest. I am using a Shutle An35N which is Nforce2 Ultra 400, PC2700 Crucial 2X256, and an XP1700+. The temp doesn't change at all going from default (133X11.5) to 166X11. Remains 42C under a Thermalright SLK-800 and 78 CFM fan. Runs perfectly stable for 24 hours on 3dmark 2003 at 166X11. ANyone have any ideas?

 

[Skitzer]

I have the same mainboard and have had no problems with it. I run my XP1800+ at 200x10 at 1.65v and my memory at 160, (320) relaxed settings, (I need to upgrade from this PC2400 Ram to some decent PC3200). I believe you have memory that will run at 166 and no more. Leave it at 166 and run your CPU at 200fsb. Also I'm surprised you can run all that stuff on a 300W PS, that's pushing the envelope.

 

[GreatDaleness]

Upped the voltage and got it stable as 2400+ speed. Skitzer, the memory was locked at it's highest stable setting, so that wasn't the issue. What confuses me is why I get MEMORY failure on a CPU overclock.

 

[Duvie]

I have the MN model with the onboard video.....Is there a bios or a way to change the multiplier??? I would like to drop it dwon to 12.5 or 12 and run my fsb at 166fsb and my memory insynch at 333mhz....

My 2100+ is doing 2ghz right now 100% prime tested and stable with less then default vcore. Board I have undervolts even at default speed so I don't think it is the power supply. I usually hover around 1.58v vcore, with super tight 3.3v, and 5v....

I have a 300watt non name brand. Came with case and said it was amd recommended...

 

[KF]

>.....Is there a bios or a way to change the multiplier??? I would like to drop it dwon
> to 12.5 or 12 and run my fsb at 166fsb and my memory insynch at 333mhz....

According to the other posts, there must be.

2100s have a 13x multiplier, which is a higher multiplier (13 and above). The 1800 and 1700 CPUs have the lower multipliers. Many motherboards will not cross the 12.5 to 13 boundary because they lack one wire of the circuit necessary. There are wire mods to set the multiplier to the lower group of mutipliers (5 to 12.5)


>What confuses me is why I get MEMORY failure on a CPU overclock.

Possibly a cache failure, which is on the CPU. The cache memory is probably the most sensitive part of the CPU to OCing.

 

[GreatDaleness]

ok, cache memory....makes sense.
As far as OCing, I use the latest BIOS
Under Advanced CHipset features CPU interface should be "aggressive", and system performance shoulr be "expert"
this is also the place where you customize the memory speed and timings
once those settings are done, go to the CPU Ratio/Voltage section and adjust the multiplier there.