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I agree that RAM is not expensive now. But once your
motherboard is at the maximum (as mine is at 1.5GB), one
turns to making most efficient use of the two caches that
can be used instead of waiting for the hard disk.
If you have enough RAM to hold all your data in AB's
internal cache, that is the fastest way to go.
If you have about 300MB more RAM than the data takes on the
hard disk, reduce AB's number of stocks to cache to a
minimum (perhaps 100, or even just 10 stocks). That way the
data on the hard disk will fit into Window's own cache.
Apparently Window's cache is a bit more compact than AB. I
assume AB's cache is maximized for speed rather than space.
Having data in the Window's cache means AB will have to
re-import it for each optimization pass, but that is a lot
faster than having to import it from the hard disk.
I do not have precise numbers, but I would guess using
Window's cache is about 5% to 10% slower than AB's internal
cache.
Also one can sometimes use a watchlist to reduce the number
of stocks that AB needs to review for each optimization
run.
b
--- jehmac <jehmac@xxxxxxxxx> wrote:
> Even assuming that all the data had to be in RAM at once,
> as opposed
> to being to swapped from hard disk as needed, for many
> people 1GB RAM
> is not that much these days.
>
> --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko"
> <amibroker@xxxx>
> wrote:
> > Owen,
> >
> > 10 day of tick data (what eSignal offers now) can be as
> much as
> several megabytes.
> > Five years of tick data would not fit in the (RAM)
> memory of your
> computer (over 1GB required)
> >
> > Of course you nentioned 500-tick bars but others would
> like to have
> other compression
> > so one would need 1-tick data to convince all.
> >
> > Best regards,
> > Tomasz Janeczko
> > amibroker.com
> > ----- Original Message -----
> > From: "Owen Davies" <owen5819@xxxx>
> > To: <amibroker@xxxxxxxxxxxxxxx>
> > Sent: Saturday, February 07, 2004 11:11 PM
> > Subject: Re: [amibroker] Tick charts / AFL TimeFrame
> Set
> >
> >
> > > Tomasz Janeczko wrote:
> > >
> > > > But... you can test historical tick data... if you
> use eSignal
> as your
> > > data source.
> > >
> > > Thanks, Tomasz! I'll have to look into it. I'd
> always thought
> eSignal
> > > offered only real-time and delayed data, with a
> limited amount of
> backfill.
> > > If they can supply, say, the last five years or so
> worth of 500-
> or-so tick
> > > bars on the e-mini S&P, with corresponding data for
> NQ and some
> of the
> > > interest rates--real contracts, not composite--you've
> got me
> covered
> > > already.
> > >
> > > Owen
> > >
> > >
> > >
> > > Send BUG REPORTS to bugs@xxxx
> > > Send SUGGESTIONS to suggest@xxxx
> > > -----------------------------------------
> > > Post AmiQuote-related messages ONLY to:
> amiquote@xxxxxxxxxxxxxxx
> > > (Web page:
> http://groups.yahoo.com/group/amiquote/messages/)
> > > --------------------------------------------
> > > Check group FAQ at:
>
http://groups.yahoo.com/group/amibroker/files/groupfaq.html
>
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> > >
>
>
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