NetNews Usenet Archive 1992 #20/NN_1992_20.iso/spool/comp/sys/amiga/hardware/15170

Internet Message Format | 1992-09-10 | 1.2 KB

Path: sparky!uunet!spool.mu.edu!darwin.sura.net!wupost!waikato.ac.nz!comp.vuw.ac.nz!am.dsir.govt.nz!peterm
Newsgroups: comp.sys.amiga.hardware
Subject: Re: SetCPU
Message-ID: <[e-mail]>
From: [e-mail] (Peter McGavin)
Date: 11 Sep 92 17:35:44
Sender: [e-mail]
References: <[e-mail]><[e-mail]>
Organization: Dept. of Scientific and Industrial Research, NZ.
In-Reply-To: [e-mail]'s message of Wed, 9 Sep 1992 07:24:47 GMT
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Two posters have recently advocated "CPU BURST" in the Startup-Sequence to
get the best performance out of an A3000.  That command turns on both
instruction-burst and data-burst modes.

It seems surprising, then, that the OS does not enable data-burst by default.
However I suspect there is a reason why it doesn't, i.e, that data-burst
slows most programs down slightly.

My understanding is that data-burst causes every data memory reference to
also reference the adjacent 4 longwords in burst cycles.  So, unless the
surrounding 4 longwords are being put to good use (and usually they are not),
bandwidth is wasted.

--
Peter McGavin.   ([e-mail]  or  [e-mail])