a7v400-mx and 400 mhz FSB

[larry venable]

I've set up a system with a atlon 3200-400MHZ FSB porocessor, but used
PC 2700 memory (ie 333 FSB memory). So it will only boot to xp2500 (at
333).

So, did ASUS lioe and just forget to tell us that while the mobo only
supports PC 2700, you gotta buy PC3200 to boot to 400FSB speeds??
Larry

 

[DonC]

I've set up a system with a atlon 3200-400MHZ FSB porocessor, but used
PC 2700 memory (ie 333 FSB memory). So it will only boot to xp2500 (at
333).

So, did ASUS lioe and just forget to tell us that while the mobo only
supports PC 2700, you gotta buy PC3200 to boot to 400FSB speeds??
Larry

Did you set the CPU Bus to 400MHz using the dip switches? And then let the
BIOS detect the memory speed automatically -- by SPD?

Everything in the manual seems to indicate that's the approach. For a
while I had my A7V880 running the CPU at 266MHz while the memory ran at
333MHz. I know that's the opposite of your situation but it proves they
don't have to be operating at the same frequency.

FWIW

 

[Paul]

I've set up a system with a atlon 3200-400MHZ FSB porocessor, but used
PC 2700 memory (ie 333 FSB memory). So it will only boot to xp2500 (at
333).

So, did ASUS lioe and just forget to tell us that while the mobo only
supports PC 2700, you gotta buy PC3200 to boot to 400FSB speeds??
Larry

The manual only shows "By SPD, 133, 166" for DRAM speed. When you
set the DSW DIP switch to FSB400 and use "By SPD" for the DRAM, what
does the board use for the DRAM ? Did it go to DDR400, which appears
to be impossible (i.e. there is no manual speed selection for 200
shown in the manual - maybe it is in the actual BIOS) ? I don't think
the board can ignore the setting of the DIP switch, unless it has a
jumperfree option in the BIOS.

I presume you tried it and the board crashed.

If you select 166 with the DIP switch, select 166 for DRAM speed,
shut down, set the DIP switch to 200MHz, what does the board do
then ?

I have noticed in just a few Via chipset boards, that the DRAM speed
won't go below the FSB speed. For example, a FSB266 processor can
use DDR266, DDR333, DDR400 ram, while a FSB333 processor can use
DDR333 and DDR400 ram. Via has a habit of reusing technology, so
perhaps this restriction exists in all their chipsets ? In any
case, I think you are right, that unlike the A7V8X manual, there
is no table showing possible combinations of FSB/DDR. If the
trend I noticed continues with your chipset, there doesn't
seem to be much point in offering FSB400, unless the DRAM speed
field in the BIOS has a "200" choice, in addition to the 133 and
166 choices.

Nforce2 boards don't have this limit, and the DRAM can be operated
faster or slower than the FSB. The only board I wouldn't buy, is
the A7N8X-VM or VM/400 (due to it having a similar limit on maximum
DRAM speed - using DDR400 causes the graphics core to screw up).
There are very few Asus microATX boards I would be interested in
buying (the P4P800-VM is the only one that comes to mind). And
changing vendors won't necessarily help, if the limits are in
the chipsets themselves. It would seem the inclusion of graphics
in the Northbridge, as well as support for DDR400, is just too much
for the typical chipset to support.

Depending on your memory, you could try overclocking it, if there
is room to bump up the timing numbers. For example, if the RAM
runs at 2-2-2-6 normally, you could try 3-3-3-8 at DDR400, and
it might work. According to one article I read, just bumping Trcd
is considered to be one ingredient to overclocking.

Good luck on your class action suit

Paul

 

[abosworth]

Class action suit is right! but not because the motherboard is
incapable of running a 400mhz fsb processor at top speed with only
ddr333mhz memory, because it indeed is able to do that very well, but
because the printed manual (at least mine) is blatently INCORRECT in
its dipswitch setting for 200(400mhz fsb)
please see this image which compares my printed manual with an online
pdf of the same manual :
http://alibosworth.com/transfer/a7v400_problem.png
i had been struggling with this for a long time, and had phoned asus,
who very unhelpfully told my that my processor must be running too hot
(it was at 45C), or that my psu was faulty.
by the way my board is the a7v400-mx rev 1.03 and the processor was an
xp 3000+ 400mhz fsb.
at the very least i want asus to publish a notice in the faq/knowledge
base database for this board.
hope this helps you out.
ali