Is this thing too fast to OC ?!?!?

[6502kid]

I recently built myself a new computer. Since I have been working with computers supplied by my employer(s) the last 15 years or so, I havent actually tried to overclock much since I replaced my 8088 chip with a NEC v20 to go from 4.7mhz to a blazing 5mhz ! I have been working building servers, programming and doing network administration for years, so I have a vague idea of what I am doing.

Back to the present:

I have the following installed in a big Enlighten ATX case, 800EB, 256mb PC133 RAM, ATI Magnum Xpert 2000 graphics card. Added 2 extra 80mm fans and drilled out the holes in the front of the case some to increase air flow. (This lowered the board temp reported by CPU cool from 33c to about 24-25c ave.)

Is stable as a rock at 800mhz 133. Got a fairly big performance boost by setting the memory to turbo and CAS2 in the BIOS. See attached memory benchmark from Sandra. In spite of some reviews of the VT6X4 I read that said it had some problems with memory bandwith, my system seems to be doing OK. The CPU benchmark lands right where you would expect for 800mhz.

Unless I am mistaken, feel free to let me know if I am, the only OC options for this CPU will be to try 140 or 150 fsb speeds to get to 840 or 900mhz.

When I try this, the computer is stable in DOS. Can run DOOM or Redneck Rampage with no problems, but when I go into windows with the higher FSB, I get various invalid instruction errors, page faults ect.

I attempted to turn the DRAM clock to HOST-PC, but the errors still occur, so I don't think it is my RAM. (It seems it would be pointless to reduce memory performance by 20% to boost CPU speed 5% it that was the case anyway.)

I suspect the problem is either voltage related, or with my ATI graphics card. (2xAGP, 32mb)

At the moment, I am back down to 800mhz and 133fsb, but I have left the voltage at 1.7 up from the default of 1.65. Will this help to maybe "burn in" this thing a bit and perhaps make it more stable at 140/150 fsb ? **Caution to any of you playing with this VT6X4 motherboard. When I went to set the BIOS settings back to default, the CPU Core voltage was flipping to 2.05 when I selected CPU default. Had to leave it at User Setting to stay at 1.65/1.7 !

Any suggestions on how to get stable at higher fsb with this setup would be appreciated.

6502kid

 

[dadx2mj]

The EB proscessors don't have a lot of room to over clock. You don't mention anything about what het sink fan you are using or what you CPU temps are. If you are using stock HSF you might want to replace it with and Alpha or something. You might try change to cas3 just to see if it is your memory that is holding you back. You might be be able to get better performance with slower ram but faster CPU if not you can always put it back to cas2 and slow down CPU but at least you would know what is holding you back. Or you could always go for some PC-150 Good Luck

 

[sylor]

Turn your ram mhz from Host PC to Host PC-PCI CLK, then you'll be able to run anything stable. When your FSB is 140 or above and your PC133 ram just cant keep up with the fast FSB.

 

[nicco eneidi]

yeah up the voltage to 1.80 volts.

 

[nicco eneidi]

yeah up the voltage to 1.80 volts.

 

[JaY_III]

keep your ram at cas 3 whle testing new FSB speeds... then when you have your FSB try changing the speed of the ram... 150FSB will be very hard to run your computer at, as your ram may not like it, and your PCI cards would be at 37.5mhz. (140FSB 35PCI)

An easy way of checking if your PCI card are holding you back is take them all out of your computer and plae them in 1 at a time. That way you can find out if your PCI cards likes them or not.

I also have a harddrive that would not work at at hight PCI speeds so do watch out for that aswell....

You could always underclock to check your PCI cards and harddrive(s), and that AGP card. this would most
likely be the most simplistc way to check (ram gota go up to check) set your pci divider to 3 and your AGP to 2/3. Now set the fsb to 100. all you hardware woud be running in spec (CPU underclocked though). Now try 112FSB, pushing you PCI speed to 37.3....... now if you can run that with no problems 150 FSB may be a possibility as you now know your PCI and Harddrives can run at 37.3 (150/4=37.5) and your AGP at 74.66 (150/2=75)

So the only things that could keep you donw if ll went well with PCI and AGP, would be your RAM (that is why it would be set to cas 3 for now) or the CPU itself.
If the ram is cas 2 @133 it should (not will, should) run 150 cas 3, the CPU will be the hardest thing to get going at 150 FSB. I hope you have a very good heatsink/fan as i am very sure you will need a little more than 1.7 volts to hit your goal.

 

[playerxo]

I have a cC0 stepping 800EB overclocked succesfully at 1000Mhz (166fsbx6). It would hang at default voltage. Runs smoothly when voltage is bumped up to 1.8 Probably can go higher but 166 is the last FSB setting on the motherboard. Is there any way to bump the FSB past 166?

Using:

Asus CUSL2
Mushkin PC150 2-3-2
Herculed 3D Prophet 2 GTS

Can someone tell me why my computer isn't going crazy with a FSB of 166mhz?

 

[6502kid]

I will try some of that and see what happens.

I had tried 140 fsb with the RAM speed
set at HOST CLK-PCCLK, but I think I
still had it at CAS2 at that point.

One reason I have been real cautious about
boosting the voltage, is I have been unable
to find a thermistor cable anywhere to monitor the cpu temps. (You should have
seen the blank stares I got from the seasonal help at radioshack and some of
the local computer stores when I went looking.....)

Currently I have a CoolerMaster CPU fan
bolted to the heatsink. I was hoping that
since I am using a 370 to slot 1 adapter
which puts the CPU sticking out from the
motherboard right into my air-flow path, it
would stay cool enough.

It doesnt even look like there is a good
place to attach the thermistor cable on
this 370 adapter. Any thoughts ?

 

[6502kid]

Is this thing too fast to OC ?!?!? -- NOT ! Success !

Thanks to the advice to switch to CAS3, I
know have this up and running with both the
DRAM and fsb at 140.

Everything looks good so far.

Will let it run for a while before I try for 900mhz
at a 150fsb, which is the most I think is possible with this setup....


{¤ Intel