[conspire] Last Year's Supercomputer

[Rick Moen]

Quoting Mark S Bilk (mark at cosmicpenguin.com):

> I'll keep that in mind.  I'm now leaning toward an nForce2 
> motherboard and an Athlon XP 2500+ or 2800+ CPU, which has
> a 333MHz bus instead of 266, and 512KB of L2 cache instead
> of 256K.
> 
> I may be getting into multimedia, and I also want very fast 
> rendering of web pages, pdf files, and other such stuff that's
> currently frustrating.

You'll have to make up your own mind what's a satisfying CPU for the sort
of tasks you're going to concentrate on.  Maybe you can bring a Knoppix
disk into some stores and play around with different classes of
machines.  This will tell you more than would playing with the store's 
Microosoft-OS preloads, which have different loading characteristics
than Linux does (and are much more CPU-intensive).

As Heather says, beware of differences caused by variations in video
card performance, as opposed to between CPUs.  (Access speed and
quantity of system RAM can make a difference, too, but that's easier to
spot.)  For most purposes, I tend to think that, if you're not a 3D
gamer, then all video cards of the last five years with 64 MB or so of
video buffer memory are alike.  (AGP is nice, too.)  Thus my liking for
used Matrox G400 AGP cards, which were exstremely reliable and of
uniform parts content -- unlike, say, Diamond Multimedia cards, which
suffered the RAMDAC du jour syndrome.  

Then, too, if you pick a video card that's been stable for a while and
favoured by Linux geeks (such as the Matrox G400 AGP), then very likely
the XFree86 server for it is going to be extraordinarily well debugged
and tweaked for performacne.  Which point out why, conversely, buying a
card based on a new and exotic video chipset is a mistake from that
perspective.

> AMD lists the max power dissipation of their CPUs in the 2500+
> range as 70 watts.  If an Intel CPU is half that, the difference
> is 35 watts, which isn't all that much as far as causing discomfort
> to a person nearby (my computer sort of has to sit up on my desk
> next to me).
> 
> Is the fan/heatsink that comes with the boxed Athlon XP a good one?

I have no clue about that.  Your observations above sound reasonable; I
know only that there _seems_ to be a big difference in heat output among
currently popular CPUs.  As far as parts longevity and noise levels are
concerned, don't forget that here we're talking not just about quantity
of heat but also its concentration in one spot:  Dealing with
significant amounts of heat coming from what's practically a point
source (a CPU) is more problematic than the same amount of heat coming
from, say, a hard drive.

What I have to say about modern CPUs and video cards needs to be taken
_cum granum salis_, because I've simply not been in the market for
hardware in a good long while.  Far from attempting to do 1600x1200
screens running lots of multimedia and PDF rendering, I'm happily
sitting on a PII/366 128 MB RAM laptop with a 14" LCD screen on
wireless networking:  It's quiet, it goes anywhere, its keyboard and
pointing device don't suck too badly.

The point, though, is that aside from Deirdre's new, tiny P4 server,
it's actually one of the faster Linux boxen in the house, despite being
neither new nor fast.  So, my knowledge of modern CPUs and video
chipsets is mostly theoretical and general.

> Exabyte tape; it's plenty fast for that.

Ah, much becomes clear.

I think we've talked on the 'phone about tape backup, and I told you
about the problem with Exabyte 8 mm drives:  They're forever breaking
down, and needing to be rebuilt.  As long as yours works, great; enjoy
it.  Tape hardware tends to be endlessly fussy over the long term,
especially the several popular types that use VCR-style helical scanning
(including 8 mm), on account of their rapid wear of both tapes and drive
heads.  Non-sucky tape backup starts with DLT (which is linear
serpentine rather than helical scan), and progresses through DLT3XL,
DLT4, SDLT, DLT7000, ADR2, and LTO -- but all of those are awfully
expensive.  For personal LANs and small businesses, you still mostly
find DDS3 and DDS4.

> Good idea, but can't afford it.

Believe me, I'm with you on that more than you know.  Fortunately, $21
is pretty trivial over the long run.  

-- 
Cheers,                    I've been suffering death by PowerPoint, recently.
Rick Moen                                                     -- Huw Davies
rick at linuxmafia.com