On Sat, 17 Apr 2004 23:56:05 +0200, Halfgaar
wrote:

Mike wrote:

My mobo has a FSB of 266 officially (with 2000+ FSB266) but I will try to
manually increase the FSB to 333 with the KT333 schipset. My memory is
allready at 333, so that's why I expect a little boost.

Set the memory back to synchronous setting, 266, and leave it there. If
your memory is high enough spec to do 333 you'd have greater performance
tweaking the timings... but of course run http://www.memtest86.com for
several hours or more after any memory changes, before running the OS.


Increasing the FSB to 333 is only possible if the mainboard supports proper
PCI and AGP deviding for that speed. On 266DDR, the PCI devider is 4,
because 133/4 in computerworld is 33, which is the speed of a PCI bus. When
running at 333DDR, you need a 1/5th divider for PCI. And of course, the
same goes for the dividers of the AGP-bus. And BTW, it's questionable if
the KT333 will run at such an increase in host-clock.

So, be careful when increasing the host-clock by so much.

KT333 will run stable up to and a little beyond 166MHz FSB and can (will
unless the manufacturer of the mainboard doesn't provide the feature) use
1/5 PCI divider, there's no question about that. IIRC the AGP divider
might be at 1/2 though, 83MHz, which is within the capabilities of
practically every video card out there but I don't know for sure about the
least common chipsets, mainly Matrox, nVidia and ATI are known to work
fine @ 83MHz for the past several years.

On the other hand, using KT333's "+33" async memory bus mode, I don't
expect that to work with 166MHz FSB as 200MHz memory bus (perhaps it's
possible with the right memory but I'm uncertain of it), but any
manufacturer "should" have the bios set to revert back to sync memory bus
above roughly 160MHz FSB (or slightly lower).

So the bottom line is that KT333 is more likely to be stable at 166MHz
than 150MHz due to being over the hump to use the 1/5 PCI divider, but
again that's only the chipset and any "decent" board based around it, the
manufacturer of any particular board could even eliminate manual bus
settings altogether.