At 12:24 PM +0000 7/27/99, Enrique Montiel wrote:
>> This will probably cost you more than it's worth.
>
>This is true that it is expensive. But hey, high cost is relative to the
>demand by the consumer, right? I personally believe that the worth of a
>2300/300 is priceless because of the tremendous potential of the Duo design
>as it stands.
However, you do have to consider that its potential is limited in this
respect. Even after you overclock the bus, it's still a system built
around a 32-bit memory bus originally designed for a 68030/040, with a glue
chip to allow a PowerPC to use it instead. Performance will be poor
compared to a "true" PPC Mac at the same speed.
In fact I think the 2300 has no L2 cache. If that's true the performance
gain from a 300 MHz chip swap is not going to be anywhere even close to the
3x increase in clock rate.
>You seem to know about casting. That's great. Please tell me the difference
>between QTP and CBGA packaging. Can you direct me to some photos and specs?
I don't have any photos offhand.
QFP stands for Quad Flat Pack. The package is square with a row of fine
leads on each side. The leads exit the package horizontally, bend 90
degrees down, and then bend out horizontal again.
CBGA stands for Ceramic Ball Grid Array. The package is once again square,
but this time the leads are a grid of tiny solder balls attached to the
underside of the ceramic slab. This type of package is much more difficult
to remove than QFP, so you can be very glad that the Duo uses a QFP 603e.
(I don't know that for certain, but I'm pretty sure the Duo was
manufactured before CBGA package PPCs were introduced, so it's probably
QFP.)
>> My advice is to just bite the bullet and buy a 2400/180, which is probably
>> about as fast as a Duo/300 would be (due to the 2400's PCI architecture and
>> better memory performance). Even better, it's G3 upgradable, has a much
>> better screen, and you don't have to deal with the silly microdocks to use
>> it with peripherals on the road. Most importantly, you completely avoid
>> the tremendous risk of total failure that you would incur by hacking up
>> your 2300.
>That's a valid answer to make point. However,... it's just not a Duo. It's a
>wannabe Duo. What makes the Duo series so impressive is that PDS slot.
Sure, but the 2400 does virtually everything a Duo can (if not more), and
it's all self-contained (except of course the floppy drive). The only
thing I can think of is that the Duo can use NuBus cards through the Dock,
but of course the 2400 has a pair of PC Card slots which can do most of the
things NuBus cards can.
I don't want to rain on your parade or on the Duo, I just want to let
people know the potential risks, expected benefits in the case of success,
and possible alternatives involving less risk.
Tim Seufert
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