Philadelphia said:
I'm having trouble with an A7N8X-E board with an Athlon XP 3200. I
have2 512meg sticks of Crucial DDR 400 ram. On random occassions, and
always running Flightsim 9, my computer rebbots or locls up.
My troubleshooting technique amounted to swapping or removing just
about every component. I found that with 1 stick of ram, everything
was okay. Two sticks and flightsim crashed. I replaced the ram, again
with Crucial but a different flavor (I buy from vendors at computer
shows) with the same results.
Because it seems like running in a DDR configuration is more demanding
than not, can I place the sticks in the slots not recommended? I know
that doesn't make sense; let me try again. I want to have 1 gig of ram
(partially because I paid $200 for it) but I don't want the DDR set
up.
If having exactly the same sticks of ram is important in the DDR
setup, doesn't it seem likely that not having the DDR configuration
might be easier to run?
Anyone have any suggestions?
Thank you for your time and help;
Frank
I've been through the same exercise that you have.
When I got my A7N8X-E, I had 2x256MB Azen ram CAS3. About as
crappy as you can get (was a pull from a prebuilt system).
I found, in slot 2 and 3 (dual channel mode), I could run
it at 180MHz, at its rated timings. If I put the two sticks
of RAM in slot 1 and slot 2 (single channel mode) or if I
used 1 stick of RAM in one of those two slots, I could reach
200MHz, but would not be error free.
It was very frustrating. And, basically, the way it works out,
is every solution to the problem erodes memory bandwidth
by about the same amount, so you really cannot win, if you are
thinking that the solution will not involve buying more RAM.
The solutions are:
1) Run in dual channel mode, but reduce the bus frequency.
2) Run in dual channel mode at full speed, but use 2T command rate.
For some peculiar reason, this setting is _NOT_ in the BIOS,
and that doesn't seem to vary amongst mobo makers. To change
this setting, you need a hacked BIOS. I got two BIOS files from
nforcershq.com, by "Trat", and since I've fixed my system,
I'm using his 1T command rate BIOS at the moment. (The Asus
BIOS runs the more demanding 1T mode as its default.) But,
there is also a 2T command rate BIOS by "Trat". How command
rate works, is the memory address and command signals are put
on the bus for two cycles, but the info is strobed into the
memory only on the second cycle. This provides a full cycle
time of setup to the clock edge. But, since a bus cycle
is "wasted" (the first of the pair of cycles for the address),
that corresponds to a reduction of around 20% in memory
bandwidth. In the example below, the command + Address are
delayed, due to the heavy bus loading from a 16 chip DIMM.
It is possible an 8 chip DIMM would work better.
2T CMD Rate Command + Address signals X-----------------X
|<------>| Tsetup
___ ___ ___
Memory Clock _| |____| |____|
___________ ___
Strobe (wasted |________|
cycle)
1T CMD Rate Command + Address signals X--------X
|<---->| Tsetup
___ ___ ___
Memory Clock _| |____| |____|
___________ ___
Strobe usable |________|
3) Run in single channel mode, at the full 200MHz, but with
the loss of whatever advantage that dual channel provides.
Dual channel seems to make a difference to memory benchmarks,
but may not be quite as much of an issue in typical desktop
applications.
Since all of these solutions suck, it is time to talk about buying
more RAM. At least one poster in this group, seems to have had
the same symptoms, while running some CAS3 PC4000 memory. I saw
a similar post on one of the private forums. Now, that is only
a sample size of two, but it seems to indicate that high clockrate
capability alone, is not enough to guarantee a solution.
I bought some CAS2 PC3200 Ballistix, and that is running rock solid
at 2-2-2-6 200MHz dual channel. (The Crucial web page rates it at
2-3-2-6, but it runs 2-2-2-6 without complaint.) I haven't tried
increasing the clock, but that Ballistix can run CAS2 timings to
somewhere between 210-220MHz. Which is enough in most cases, to
run into chipset limitations or processor limitations, so you
really don't need much more capability than that.
I don't know if some Samsung TCCD CAS2 (and a certain revision of
silicon die) based memory, will do the same thing for you or not.
There are about six or so performance memory makers who make modules
based on that stuff, such as Corsair 3200XL. You may want to search
nforcershq.com , to see what the experience is with that stuff.
You can sometimes find cheap generic memory modules, that happen
to have one of those two memory types on them, but you would have
to work in a computer store, to be able to find them
Good luck - taming the memory demon on the Nforce2 motherboards,
is the hardest part of a build.
BTW - Before concluding the new RAM you buy is good stuff, run
memtest86 from memtest.org (tests for bad cells in the memory
but tests every memory location on the stick) and a Windows
program called Prime95 from mersenne.org (tests memory and
processor together, for speed faults and heating effects).
The Prime95 torture test is what helped me identify
that one of my sticks of RAM had a bad area of memory, that
memtest86 didn't pick up. That cheesy memory, by the way, had
run without crashing my other computer, for about a year!
And don't forget to turn up the RAM voltage (Vdimm) in the
BIOS. DDR400 memory official spec is 2.6 volts nominal, and
the BIOS might offer up to 2.8V or so. Use as much voltage
as it takes, to get error free operation. Excess voltage
just makes the memory warmer, but more than 2.5V is needed
to make it happy.
Paul
