[rescue] Re: AXi vs. Ultra 30

[James Lockwood]

On Tue, 7 May 2002, Robert Novak wrote:

> AXi will take faster CPUs (up to 440MHz) but only up to 1GB RAM. Uses RAM
> similar to U5/U10 in banks of two. Fun with column addressing modes.
>
> Ultra 30 will take up to 300MHz CPU but up to 2GB RAM, and two UPA

400MHz/2MB modules work, though Sun doesn't officially support them.  SME
has 480MHz/2MB IIi modules for the 5/10/AXi though remarkably few have
escaped into the wild.

> vertical framebuffers (ignore this part though). Uses Ultra 1/2 style RAM
> in banks of 4. If it works in a U1 or U2, it works in a U30.

Pairs of 2.  With banks of 4 you get interleave and increased performance,
but there is no requirement to interleave.  16 DIMM slots in the U30 so
you can get to 1GB using cheap 64MB SS20 DIMMs.

AXi can support higher UPA speeds (up to 120MHz) though this depends on
your processor (you'd need a Sabre 360 or Sapphire 480 to go that high).
U30 tops out at 100MHz.

AXi has 6 32-bit/33MHz PCI slots on 2 busses (3 and 3).  Bandwidth is
shared with onboard I/O.  U30 has a 64-bit/66MHz slot and 3 64-bit/33MHz
slots, all on private busses (slot 2 is shared with onboard I/O).

Fun trivia fact: the U30 was the first workstation to ship with a 64/66
PCI slot.  The U30 is in many ways more similar to the U60 and E450 than
the AXi with regards to how I/O is implemented.

AXi has dual onboard UW SCSI.  U30 has a single channel (U60 added a
second channel).  U30 has neato spiffy 2-slot SCSI backplane using SPUD
brackets, AXi has whatever the chassis it is in has.

Creator/Elite on AXi blocks a PCI slot (not a concern for you).

U30 can support a software-eject floppy drive (now THERE's a big feature
for you).  :)

> Depends on your priorities, really.

Absolutely.

Here's my opinion: the original poster said that case was in favor of the
AXi.  I would go for the U30 unless the case and cabling of the AXi was
absolutely immaculate, and ventilation was plentiful.  The AXi is a
terrific board but I have seen far too many of them stuffed into poor
quality chassis that induce overheating problems and make maintenance a
nightmare.

The U30 was built to a high standard, and the quality shows.  It is
nothing like the U10 inside, despite a similar outward appearance.

> I just sold my desktop AXi to go to a U30, but that was mainly because I'm
> board-swapping it for a U60/AXdp. U60 will probably kick AXi or U30's butt
> all over the place for SMP-friendly applications, but the U60s aren't
> under $500ish yet.

Good call.

-James