Very Computer

by **Dr.Ulrich Fause** » Fri, 31 Jan 1997 04:00:00

Hi,

After upgrading my 486DX2/66 to an AMD 5x86/133 and voltage regulator I
experience parity errors whenever I put something in memory bank 2.
I have 32 MB as 8 times 4 MB, five are 80ns 3 are 70 ns.
They work fine with the 486DX2/66.
Now with the AMD whenever I put only 16 MB in the lower memory bank in
whatever mixture of chips, this works fine.
But as soon as I put whatever mixture in the second bank I get parity
errors.
Sometimes immediately when booting , sometimes minutes to hours later.

Has anybody a clue what could cause this.
I think defective chips should also cause an error when they are in the
lower 16 MB.
Or are the first and second memorybanks treated differently.

BTW this happens with LINUX and WIN95

Otherwise the AMD 5x86/133 works allright.

Uli

by **Jay Thorn** » Fri, 31 Jan 1997 04:00:00

> Hi,

> After upgrading my 486DX2/66 to an AMD 5x86/133 and voltage regulator I
> experience parity errors whenever I put something in memory bank 2.
> I have 32 MB as 8 times 4 MB, five are 80ns 3 are 70 ns.
> They work fine with the 486DX2/66.
> Now with the AMD whenever I put only 16 MB in the lower memory bank in
> whatever mixture of chips, this works fine.
> But as soon as I put whatever mixture in the second bank I get parity
> errors.
> Sometimes immediately when booting , sometimes minutes to hours later.

> Has anybody a clue what could cause this.
> I think defective chips should also cause an error when they are in the
> lower 16 MB.
> Or are the first and second memorybanks treated differently.

> BTW this happens with LINUX and WIN95

> Otherwise the AMD 5x86/133 works allright.

> Uli

The main issue you have is speed of the chips. The first ram bank is
probably closer electrically to the bus transcievers, so is less timing
sensitive, but the second is fairly obviously more sensitive. At higher
speeds (and AMD's can fully saturate your memory bus, unlike 486's) you
have more problems.

My advice: Ram is cheap, buy 4 x 8 MB 60ns New Ram, and use it ONLY.
Sell your old ram to someone with a 386.
Don't mix speeds. If you insist on using your old ram, go into your
bios and add a wait state, or two.

--

--

the Net Result System Services

by **Rich McDonal** » Sat, 01 Feb 1997 04:00:00

> Hi,

> After upgrading my 486DX2/66 to an AMD 5x86/133 and voltage regulator I
> experience parity errors whenever I put something in memory bank 2.
> I have 32 MB as 8 times 4 MB, five are 80ns 3 are 70 ns.

One other thing to check: make sure your new voltage regulator is
getting the proper voltage to the CPU, preferably within tolerance on
the high side. I.e. 3.6V for a 3.45V AMD 5x86/133ADW. I have had a bad
experience in that the CPU runs fine on the low side, but the connected
periperal chips were not getting what they perceived as a proper logic 1
voltage.

Cheers,
Rich

by **Erik Ratclif** » Sun, 02 Feb 1997 04:00:00

: After upgrading my 486DX2/66 to an AMD 5x86/133 and voltage regulator I
: experience parity errors whenever I put something in memory bank 2.

You may want to pop into your CMOS setup and change your write cache wait state to 1. That may help.

by **Dr.Ulrich Fause** » Tue, 04 Feb 1997 04:00:00

> Hi,

> After upgrading my 486DX2/66 to an AMD 5x86/133 and voltage regulator I
> experience parity errors whenever I put something in memory bank 2.

Well thanks to everybody who answered.

Changing my waitstate from 0 to 1 really helped and it's now working
without crashing.

Thanks
ULI

Very Computer

AMD 5x86/133 then parity errors

AMD 5x86/133 then parity errors

AMD 5x86/133 then parity errors

AMD 5x86/133 then parity errors

AMD 5x86/133 then parity errors

AMD 5x86/133 then parity errors