From: kanefsky@halcyon.com (Steve Kanefsky)
Subject: Re: Daystar Powercache (need info...)
Organization: The 23:00 News and Mail Service
Date: Mon, 14 Sep 1992 15:24:54 GMT

In article <1913mpINNfvb@mohawk.cs.utexas.edu> newton@cs.utexas.edu (Peter Newton) writes:
>> I expect that the 33mhz '040 PowerCache due out soon will beat the
>> Quadra 700 and 900 on the Math and CPU related stuff, and be very
>> close to (possibly even ahead of) the Quadra 950 in these areas.  The
>> 16-bit data path of the LC II has very little effect once you go to an
>> external cache. 
>
>I wonder.  Just how much cache memory comes with with Daystar
>PowerCaches?  One problem with with small benchmarks like those built
>into speedometer is that they tend to fit entirely within even fairly
>modest caches.  Things might be a bit different with production sized
>apps, depending on their locality.  It would be interesting to do some
>timings with larger programs.

Ah, a perfect opportunity to present my "real-world" benchmarks.  Last
night I decided to remove the PowerCache and do some benchmarks, after
which I put it back in and ran the same benchmarks.  I tried to be as
careful as I could about not letting caches (either disk or RAM) confuse
the test results.  I always tried to flush the caches before running each
test (e.g. before running an Excel test, I would open up Word).

The results seemed to agree with the Speedometer benchmarks pretty well.
Naturally, if Speedometer says that the CPU is three times faster and the
disk is only 20% faster, than a task involving both disk and CPU will be
somewhere between 20% and three times faster.

(BTW, the answer to your question about the cache is that it's 32K
direct-mapped)

So, without further ado, here are the benchmarks I ran and the results:


Boot time from Restart (with just the          32 sec               28 sec*
Daystar PowerStation control panel)


Boot time from Restart (with a dozen           52                   40*
or so extensions)


Time to launch MS Word 5.0                     24                   12


Time to launch MS Excel 4.0                    29                   16


Time to launch MS Excel 4.0 (with several     117                   50
linked worksheets and add-ins, including
the time to finish re-calc)


Time to uncompress and display GIF file        32                   12
in Giffer 1.2 (503K after decompression)


Time to de-binhex 303K .hqx file in DeHQX      43                   22**
(216K after de-binhex-ing)


Time to compile Art Class demo in THINK C     1045                 386
5.0 from scratch


----------

* Note that the PowerCache boots with it's 32K cache off, eliminating a
lot of the advantage until the PowerCentral control panel loads and turns
on the cache.  Loading PowerCentral first speeds up the rest of the boot
process.


** It was very clear in the DeHQX test that disk access took most of the
time.  The program would just fly through a chunk of the decoding process,
then sit there and wait while it wrote out to disk, then continue with the
next chunk.  I didn't get a chance to test this with a RAM disk, but I
suspect the difference would have been much greater.

I may do another round of benchmarks, so if anyone has any specific
suggestions on what to test (you can send me sample documents if you
wish), I'd be happy to try them out.



Thanks,
--
Steve Kanefsky