Strange Memory Behaviour

[-sam-]

Hi there,

I recently experienced some strange problems.
I upgraded my A7N8X with 2 512MB 200MHZ DDR Ram Modules (Kingston).
I have them running at 200MHZ/Dual Channel Mode (400Mhz).
Everything runs fine on my computer.. my Games
3dsmax.. etw. expect FS9.
After about one minute of flying I get strange errors like
my computer freezes or I get a Bluesscreen "IRQ not less
or equal" or the PC reboots immediately. After
a whole day of testing different possible reasons
I figured out that FS runs stable when I force my memory
to 166 MHZ btw. 333MHZ Dualchannel.
I thought it

[Delta_]

Out of curiosity what CPU are you using?

[-sam-]

I have an Athlon XP 3000+ running at a multiplier of 12.

The next "funny" thing.
When I run it on 12.5 (Bios still says 3000+)
it also crashes FS but the rest of the system runs fine.
The temperatures all seem ok.

It

[Delta_]

You should be running your memory at 166Mhz in-order to have the same speed as your CPU bus.

[Gixer]

I think I see your problem!

The XP3000+ Barton cpu is only 166Mhz (333 total)

You running it at 200fsb ok so 200*12.5 = 2500MHz

I'm sure its default speed is about 2150Mhz or there abouts.  I would try lowering your multiplyer to 11.

Saying that your CPU may not be a 'Good' one and it may not be able to hold 200FSB.  You could try upping the voltage to your CPU a bit to see if that makes it more stable, but beware doing this will make it run hotter!!

I think your default settings should be 166MHz (333 total) mulitplyer at 13 giving 2158MHz.  Set to this and test FS9.  If it runs stable then its the way your overclocking that is causing the instability.

What I would do in your situation is this.  If the CPU cant handle the higher FSB do not worry.  Leave the FSB at 166 in BIOS.  Goto your ram timings.  Try and get the ram running at 11-2-2-2  If I remember right your mobo has a nForce 2 chipset?  they liked 11 at the start, though my PC did bench ever so slightly better at 5-2-2-2 which was kinda weird.

You have to remember you have brought ram that is capable of higher speeds than the cpu was intended too.  PC2700 ram woulda done the job fine.  But using the ram you have just brought I reckon you can do a bit of tweaking, you just gotta find the stable point.  I had an XP2800 Barton CPU.  I put Corsair 200MHz FSB stuff in.  I had the same problems my CPU couldn't hold 200FSB without voltage increase and heat was an issue so I quit on that idea as it became unstable.  I then just played with the ram timings.  This had great results and by tightening the timings it benched much better results.

[-sam-]

Thank You very much !!

That makes sence
I really thought the 3000+ is a 200mhz CPU.
So I

[Gixer]

I think there may have been a 200FSB variant but the ones I looked at on the overclockers site are 166FSB.  If I remember right there may have been unstability probs with the 200FSB version on certain mobos, though I cant remember.

They are multiplyer locked though I am pretty sure, so if your max multiplyer value available in BIOS is 13 I would say you got a 166FSB one.  There is a number you can get off your CPU and from that you should be able to tell what FSB speed it is.  Gonna be pretty hard gettin to see it with the fan on it though!