64 meg v. 128 meg; 4 gig v. 8 gig

Tim Cutts tjrc1 at mole.bio.cam.ac.uk
Tue Apr 29 11:39:01 EST 1997


In article <5k4vl7$dqk$1 at dns.ktb.net>, Albert Gold  <bgold at ktb.net> wrote:
>OK, so making the assumption that the facts of the Wisconsin
>Package remain as they are, I need to purchase a unix box.
>
>I am looking into a SUN Sparc. or Ultra as the least expensive
>alternatives to serve a group of 8 or so users.
>
>GCG recommends 64 meg of RAM. Why buy more?

Because some GCG programs are serious memory hogs.  Their blast
implementation is memory-inefficient, and often asks for 64 MB.  This
means that on our 128 MB machine, having two blast searches running
simultaneously causes the machine to start swapping, although hardly
seriously.  Three or more, and it starts becoming a problem.

If you build your own indexes, you will need *much* more.
gcg_srsbuild requires *huge* amounts of memory (up to 150 MB while
building EMBL indexes, for example).  If you don't have enough, it
will thrash the hard disk like mad and take an age to run.  Updating
the EMBL SRS indexes takes over ten times longer on our 128 MB machine
than on our 512 MB machine (admittedly the 512 MB has a faster
processor too, but only by a factor of three or so).

Basically, buy as much RAM as you can afford.  Having a whizzo fast
processor is a waste of money if you have so little RAM that the
machine has to swap to disk all the time.

Tim.






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