Hello, Jean.

-=> JEAN PARROT wrote to JEFF GUERDAT <=-
Looks like Jeff didn't get your msg, or he may be on vacation, so I'll
give it a go.  Some of this duplicates things we've already talked about
via email.

Thursday night, I finally saw a board with one of those VIA C3 800 chips
on it where I volunteer.  It was a cute little board,  smaller than
Micro-ATX, and with only one PCI expansion slot.  Most everything else
is already on the board - video, sound, NIC, etc.  I put some memory in,
put it in the test-bed, and it sprang to life - - booted to FDD and HDD,
so next week I'll look for a mini-desktop ATX case to put it in.
Although the 800 speed is pretty fast compared to most of the
"donations" we receive, there are a few disadvantages to this little
board - - it only has one IDE channel, and the CPU chip is soldered
directly to the board.

 JP>         Can you explain this? In my BIOS for this VIA 800, I see under:
 JP>         VIA C3 Clock ratio this :  Default
 JP>         Current Host clock      :  133 ( I can toggle it to 166 )

That 133 sounds right - - from VIA/Cyrix website, the C3 800 uses FSB of
133, so the CPU's locked clock multiplier would be 6 to get 800.

 JP>         Current DRAM clock:  100 ( I have two choices 100 and 133)
 JP>         and at the end of this line : HCLK -33

Via email, you say that you have PC133 memory sticks, so I think this
should be set to 133 as well.

 JP>  In my mind, these are reversed, I think that the Host is the CPU
 JP>   and DRAM is memory sticks.

That would be correct.

 JP>  When I first built this system about
 JP>  one year ago now, it came up on BIOS as both at 133, so I left
 JP> them there. A techie told me that the VIA 800 would run better
 JP> at 100

I can't imagine why he/she would have said that.  If it shows
instability at the intended 133 FSB, I think I'd try 125, or 120, or
something like that before going all the way down to 100.

 JP> and I find that it is quite a bit faster if I set the
 JP> DRAM clocl at 100 and leave the Host at 133. This is where my
 JP> mind is confused. I would have thought that the Host should be
 JP> set at 100 but it is at the smallest value of 133.

Hee.  Set the DRAM clock back at 133 and it should speed up a bit more.
You might recheck what I said above at the VIA website.  Per what I saw
there, your host bus (FSB) should be at 133 for the VIA C3 800.

 JP>         The VIA C3 clock from Default, can be toggled to 3.5, 4, 4.5,
 JP>         5 etc. Are these overclocking rates ? My pamphlet is not too
 JP>         explicit and obviously not meant for the home fixeter.

Yep, Mainboard user manuals can be pretty disappointing, particularly at
the "low end".

I think your chip's default value is 6, and should be left there.
I can't say for sure about the VIA chips, but Celerons have a "locked"
clock multiplier in them.  Mainboard BIOS may let you "underclock" them,
but putting in an overclocked value of CPU clockmultiplier by jumpers or
in SETUP would usually result in system appearing to be "dead".
These days with most chips having a locked clockmultiplier,
those intent on overclocking must generally do it by overclocking the
FSB and/ or the memory bus.

Good luck - - -  JimH.

... Bother! said Pooh, as his system again locked up.
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