[geeks] thoughts.

[Gregory Leblanc]

On Fri, 2002-05-03 at 23:11, Chris Byrne wrote:
> > -----Original Message-----
> > From: geeks-admin at sunhelp.org [mailto:geeks-admin at sunhelp.org]On Behalf
> > Of Bill Bradford
> >
> > I think 64meg (maybe 128s?) in the '20,
> 
> Found it. According to Birdsall the SS10 and SS20 have a max ram of 512m
> with a max simm size of 64m
> 
> > quad 200s is asking for trouble; I heard a story of a guy who
> > came in to work on a MOnday to find the top of his '20's case melted over
> > the CPU section...
> >
> > I'd kill for a nice pair of SM71s or even SM81s.
> 
> I suppose I could do a little case modding to deal with the heat of the
> 200mhz ross modules, but a pair of SM81's would be cool (literally and
> figuratively).

Well, not "cool", but cool enough that the SS20 could handle them,
though you'd probably want it air-conditioned.

> I've played with a bunch of SS10's and SS20's but they've all been single
> proc. I havent had any experience with the multi-proc systems and I've got a
> few questions.
> 
> 1. Would the SM520 be the fastest dual processor Mbus module that work with
> the SS20?

Uhm, No.  That's the fastest SuperSPARC, though (AFAIK).  The 150MHz
HyperSPARCs (with .5MB of cache) should also work, though you'll be
pushing it on cooling with them.  

> 2. Which would be faster for a good mix of multi threaded applications, dual
> SM81 (2 procs total) or dual SM520 (4 procs total)?

Probably the SM81s.  The spec numbers might be worth looking at, though
I don't have any links handy (google turns them up eventually).

> 3. Would two ross dual proc 142Mhz 1mb modules or two ross dual 125mhz 1mb
> modules work config and heat wise? As far as I can tell they are the fastest
> dual processor module with 1mb of cache.

Config and heat, probably.  I'd bet on the SM81s out running the 125MHz
modules, though.  At least for any load that required context switching.

> 4. Would I be correct in assuming that the massive increase in clockspeed
> would make up for the architecture differences between the HyperSPARC Ross
> modules above and the SuperSPARC-II sm81?

Yeah, the 150MHz modules with .5MB of cache are, I think, about 10%
faster than the SM81s.  I've never actually seen any 200MHz modules, but
they ought to be quite a bit faster.

> 5. Assuming I COULD get it to work heat wise would the 200mhz clock speed
> and larger l1 and othjer achitecture inprovemnts in the 620d make up for
> having half the cache at half the speed as the 620c 142Mhz modules? I have
> the suspicion that it wouldnt, but I may be wrong.

Not sure.  The context switching technology is the same for both.  The
200MHz modules seem to fetch a fortune whenever I've seen them for
sale.  Maybe when they're dropped from the current version of Solaris
(10?) people will realize that they're "useless" and the prices will
come down.

> 6. Would one of the clones (say an axil s/420) have good enough, or be
> easily moddable to provide enough cooling for the quad 200mhz?

A clone?!?  Shame on you!  :-)  I have no idea.  The SS20 is easily
moddable, though.  Replace the power supply fans with something with a
much higher FPM rating, and put a set of fans with a high FPM rating
along the other side of the case.  I'll bet that would keep them cool
enough that you don't need to worry, but grab the temp probe for your
DMM, run the machine and a couple of XFree86 compiles for a few hours
and find out.
	Greg

-- 
Portland, Oregon, USA.