On Tue, 27 Mar 2001, Xavier HUMBERT wrote:

> In message <3AC0D2A0.14606.4491C6D9@localhost>,
> Thomas Michael Wanka wrote:
> 
> >When searching for CPU cards it looks like many G3/4 cards seem 
> >to need some (MacOS) software to run properly or use the cache 
> >or something. 
> >
> >Will the backside cache work under NetBSD and is there 
> >performance improvement if the cache is 1MB not 512K? 
> 
> I actually use a Sonnet Crescendo G4/400 on a 8600, which is basically
> the same as a7500/8500. Just plug an reboot :-)

	Why would you throw away ~$400 on a G4 CPU that wouldn't help you
anywhere near as much as a motherboard upgrade would. You could grab a
Beige G3 MT or DT on Ebay for about $500 and get a ZIFF CPU upgrade from
OWC for about $130 and have yourself a G3/400 with three PC-100 SDRAM
DIMM's, DMA IDE (5-10MB/sec), onboard ATI Rage M64 or Rage Pro depending
on motherboard revision, OF 2.x instead of 1.0.5, 66MHz PCI bus (I think),
for about $50 you could get a 128MB DIMM, and it would come with at least
a 4GB IDE HD, 24X+ CD-ROM, etc. etc. 

	IMHO there are three things that bog down Mac's in general: 
1.) slow bus speeds (PCI and System)
2.) slow video hardware
3.) "ultra" slow HD controller transfer rates (for both SCSI and ATA/IDE)
4.) Not enough RAM
5.) under powered CPU

	Upgrading a CPU only solves one of those bottlenecks, upgrading to
a different computer/motherboard doesn't solve the others, but it would
certainly be an improvement over an upgraded 8600. Try spending some time
figureing out what your computer is doing while you're waiting. If it
spends a long time before OFW comes up, the RAM and System bus is probably
slow, if launching programs and starting MacOS (with VM off) uses a lot of
disk activity, the hard disk chain isn't up to par, etc. etc. You could
use netbsd profiling tools to figure out what's slow on your computer, and
things like vmstat -i, top, systat, etc. 

	While all this has little to no base on actual facts or testing, I
think you'll find that the CPU isn't often the bottleneck on MacPPC
systems, and if it is, it's probably because of non-DMA transfers. 

	I should also point out that, if you ever want to try Mac OS X,
you're machine will probably not be able to boot it (without weeks of
hacking OS code), and older machines accelerated with a G3/G4 upgrade are
not supported by Apple at all. buuuut, if all you want to do is run NetBSD
and MacOS, a Medium speed G3 upgrade would be a cheap way to get better
preformance.


</Rant> </Ramble><P>



Chris