Hi,

Recently I upgraded my SS20 to have 2 CPUs. I've bought 2 180MHz
Rosses, and installed them as well as 2.25R boot prom. When running
single CPU configuration, everything is fine, but with 2 CPUs also
everything is fine until I start doing something CPU intensive, like
compiling, etc. System just hungs or crashes. If the system is idle,
then it's fine. I tried both CPUs in Mbus slot 0 (sigle CPU
configuration), and everything works fine. What can it be? Maybe
overheating? But why the system is stable when idle then?
Any ideas?

yugi wrote:
> Hi,
>
> Recently I upgraded my SS20 to have 2 CPUs. I've bought 2 180MHz
> Rosses, and installed them as well as 2.25R boot prom. When running
> single CPU configuration, everything is fine, but with 2 CPUs also
> everything is fine until I start doing something CPU intensive, like
> compiling, etc. System just hungs or crashes. If the system is idle,
> then it's fine. I tried both CPUs in Mbus slot 0 (sigle CPU
> configuration), and everything works fine. What can it be? Maybe
> overheating? But why the system is stable when idle then?
> Any ideas?
>
Heat?

--
Mauricio raub-kudria-com
(if you need to email me, use this address =)

yugi wrote:
> Recently I upgraded my SS20 to have 2 CPUs. I've bought 2 180MHz
> Rosses, and installed them as well as 2.25R boot prom.
snipped
> Maybe overheating?

Use psradm to offline one of the processors and give the box
something CPU intensive to do. Then switch the offlined CPUs.
(offline the second instead of the first). Its likely heat, bad
CPU, or possibly a motherboard issue ..
Anyway I used this method once to find a bad CPU.

Yes, it worked fine with each CPU, but with both it was freezing at
some point. Looks like overheating. I'll try to replace my power supply
and maybe add some additional fans.

"yugi" <yuri123@gmail.com> wrote in message
news:1125420888.639070.163180@f14g2000cwb.googlegr oups.com...
> Yes, it worked fine with each CPU, but with both it was freezing at
> some point. Looks like overheating. I'll try to replace my power supply
> and maybe add some additional fans.
>

You don't need additional fans, my SS20 with dual CPUs works just fine, even
when it's over 80 in the computer room. Personally I suspect a motherboard
problem, do you have access to another SS20 to try some part swapping?
They're not too hard to come by, found mine for $30.

I replaced the motherboard. The same thing. I think, it's overheating,
but I've got another rack mounted case where I can test it. Also I have
another 2 60MHz Supersparc CPUs and will test how do they work in pair.

yugi wrote:
> I replaced the motherboard. The same thing. I think, it's overheating,
> but I've got another rack mounted case where I can test it. Also I have
> another 2 60MHz Supersparc CPUs and will test how do they work in pair.

Im guessing they will be fine. My SS20 has dual 70's and I never
had a problem with overheating. The 180's are noted for heat as I
recall..
These are "matched" CPUS I assume - as in the same mask..? serial
console should reveal that.
Leave the top off and point a big fan at the 180 cpus.. See if the
box stays up.

<gerryt@vcn.bc.ca> wrote in message
news:1127507750.884353.6280@g44g2000cwa.googlegrou ps.com...
>
> yugi wrote:
> > I replaced the motherboard. The same thing. I think, it's overheating,
> > but I've got another rack mounted case where I can test it. Also I have
> > another 2 60MHz Supersparc CPUs and will test how do they work in pair.
>
> Im guessing they will be fine. My SS20 has dual 70's and I never
> had a problem with overheating. The 180's are noted for heat as I
> recall..
> These are "matched" CPUS I assume - as in the same mask..? serial
> console should reveal that.
> Leave the top off and point a big fan at the 180 cpus.. See if the
> box stays up.
>

I have a SS20 with dual 71's and have had no problems with heat, even when
it's 80+ degrees in the room the machine has been rock stable. Perhaps the
power supply is marginal? A second CPU adds quite a bit of load.