Besides other nefarious things I'm known for, I am also a Compaq ASE, so
hopefully that'll carry some weight in my response. :)
> > I have just upgraded a Proliant 2500 from dual PPro 200's to dual
Pentium II
> > 333 overdrive processors. ...
> > Now before I upgraded, I was running double check's on 2 exponents,
668xxxx.
> > I was getting about .515 second iteration times.
> > Now that I have upgraded, I am only getting .448 second iteration times.
>
> Might it just be the effect of slower cache? As I recall, the numbers
were:
>
> P Pro 256 or 512K one CPU clock to deliver data
> P II 512 K two
> Celeron 128 K one
>
> and on some tasks, Celeron outperforms P II at the same clock because of
> this.
One problem is most likely due to the Pentium II Overdrive's cache
architecture which, if I recall correctly (I hate abbreviations), runs at
half-speed like the other PII's.
The PPro cache ran at full speed, and the Proliant 2500 (and I've got a
couple of the 2500's around) came with 512MB L2 cache chips, but could be
ordered with the 1MB or 2MB L2 PPro's also... believe me, even on a 200 MHz
machine, that extra cache, and running at full speed, does make a
difference.
Sure, a PII running at 333 would be faster, but you have to deduct "speed
points" for the smaller cache (256K I think) running at half the full speed
(166 MHz, even less than the cache on a PPro 200)...
Also, please DO NOT DO NOT DO NOT DO NOT replace the BIOS chips on your 2500
with the E50 BIOS. There are a LOT more differences in the systemboards for
a Proliant 2500 E24 (the PPro system board) and the E50 board (the PII
board).
Not only would those BIOS chips not work, but they would *really* not work
(I'm not sure what that means...)
The odd performance stemming from running NTPrime on both CPU's is a direct
result of the memory architecture not being optimized for PII accesses and
speeds.
The E24 board was made to work great at handling mem requests for a pair of
PPro's. Compaq does a GREAT job at SMP architecture, even on their older
boards, using their custom chipsets and all that (much better than
off-the-shelf dual CPU boards).
However, when you go beyond what the motherboard was designed for, the peak
performance of the mem architecture goes away.
I would say that the BEST option you could come up with would be to forget
the PII Overdrive chips (they're almost worthless, in my opinion, performing
worse than a regular PII at the same speed... go figure. It shouldn't be
that way, but that's my experience...
The thing to do is to get the PPro-Celeron socket adapter from Powerleap
(www.powerleap.com). They're compatible with the Proliant 2500 (and a few
other dual PPro machines)... One caveat... you can get 2 upgrades for your
2500, but due to some physical constraints, some people have been forced to
shave off a few millimeters of PCB to get both CPU's working in the 2500...
but it can be done.
Another caveat... only the older Celeron 550's are dual CPU capable... the
newer ones are now missing that capability altogether. Powerleap sells kits
of 2 Celeron 550's that are SMP capable, so that's one way to go.
Another way to go is to forego the dual CPU and just get the fastest single
Celeron they support, which is a Celeron 766MHz (the fastest 66MHz Celeron
there is).
Given the trade-offs of running dual 550's or a single 766, you might get
better performance with the single, faster CPU than with 2 slower ones...
only some benchmarks of either would really tell you though. Hmmm...
I'm currently debating which way to go on that for the 2 Proliant 2500's I
currently run. I'm leaning towards the single faster option for my own
machine, which doesn't really need dual CPU's for much, and getting the dual
550's for the server at work since it does more things. Hey, that way I can
tell you all which works better at NTPrime. :)
To sum up:
... E24 boards don't work with E50 BIOS (there's actual physical differences
in the board, which should be obvious since one is socket 8 and one is Slot
1. :)
... PL-Pro/II upgrades using Celeron (cache runs at full speed!) are a MUCH
MUCH better option than the cheesy PII Overdrives (if you can even find one
of those dinosaurs)
... Besides NTPrime, judge whether dual Celeron's at 550 would be better or
worse than a single Celeron at 766.
Aaron
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