Date: Tue, 10 Jun 1997 06:58:14 -0700 From: "Michael L. VanLoon -- HeadCandy.com" <michaelv@MindBender.serv.net> To: Tom <tom@uniserve.com> Cc: Satoshi Asami <asami@cs.berkeley.edu>, burton@bsampley.vip.best.com, current@freebsd.org Subject: Re: overclocking Message-ID: <199706101358.GAA17309@MindBender.serv.net> In-Reply-To: Your message of Mon, 09 Jun 97 23:21:59 -0700. <Pine.BSF.3.96.970609230318.21828A-100000@shell.uniserve.com>
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>> >However, I suggest you invest some money on SCSI drives before you
>> >even try overclocking. (Get the 8ms/7,200rpm variants too --
>> >10ms/5,400rpm won't do much better.) The bottleneck of your machine
>> >during compilation should be the disks, not the CPU.
>> You're betting off buying two 2GB 5400RPM drives and striping them
>> with ccd, than buying one 4GB 7200RPM drive. You *will* get better
>> performance in almost all benchmarks, and most real-world use.
>> Trust me. Stripe your drives. It's worth it.
> A couple of issues:
>- The best quality drives are 7200rpm only
How does quality equate with rotational spin? Actually, 7200RPM
drives are much more likely to melt down if you don't cool them well.
Which would make 5400RPM drives, on the average, more reliable.
>- Striping two 7200rpm drives is even better than striping two 5400rpm
>drives
This is true. It's also a lot more expensive.
>- Putting /usr/src and /usr/obj on separate drives is probably better than
>stripping, because you know that accesses will happen in parallel. But
>again, this is optimization specific to world building, not general-use
>systems.
Putting /usr/src and /usr/obj on separate striped ccd partitions would
be even faster. :-)
>- Striping is not going to improve seek performance
Sure it can. Especially with tagged-command-queuing. You have
multiple mechanisms seeking simultaneously. That would be faster than
trying to move all the data through one set of heads, which can only
be at one location at any single point in time.
> As far as Joe Greco goes, he has been huge proponent of using large
>numbers of 5400rpm, but that's his opinion. I prefer fewer, but faster
>drives. I don't believe Joe has ever tried building a system with mostly
>7200rpm drives. Anyways, I get a newsfeed from Joe, and provide some
>charity feeds to some ISPs...
>
> Anyways, I won't get anything but 7200rpm drives these days, but I also
>need all the performance I can get.
I'm glad you can afford all those 7200RPM drives. :-)
However, a question you might ponder: are you faster with a few
7200RPM drives in a ccd than you would be if you spent that money on
two or three extra 5400RPM drives and made your ccd consist of more
drives?
I'll bet there's an interesting trade-off there.
-----------------------------------------------------------------------------
Michael L. VanLoon michaelv@MindBender.serv.net
--< Free your mind and your machine -- NetBSD free un*x >--
NetBSD working ports: 386+PC, Mac 68k, Amiga, Atari 68k, HP300, Sun3,
Sun4/4c/4m, DEC MIPS, DEC Alpha, PC532, VAX, MVME68k, arm32...
NetBSD ports in progress: PICA, others...
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