connery@bnrmtv.UUCP (Glenn Connery) (01/23/86)
Since I've received some queries... the following information off PCShare
is provided for your information...
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Append on 01/12/86 at 13:20 by Charles Daney:
How to make a faster AT.
Here is some information from Compuserve via The Well on speeding up an AT:
Item 46, response 12 (of 12), by Jonathan Sachs (jonathan)
Fri Jan 10 19:53:41 1986 - 67 lines.
Courtesy of Stephen Sisler, here is some interesting information about
products that will speed up the PC AT. I got it from messages that
Stephen left in the IBM PC AT forum (PCS-131, subtopic 4) of CompuServe.
Stephen's account
there is 72366,3724.
80286s: 10mhz are going for $250-$300. 12mhz for $350-$400 retail. 14mhz
are supposedly available for $$$$. Some ATs will run at 16mhz. Reportedly
these are the new C6 or E2 versions that fix the protected mode bug
that plagued DRI.
80287s: Even when you're running your 80286 at 9 or 10mhz, your 80287 is
still running slow, because while the 80286 is driven at 1/2 the xtal
speed, the 80287 runs @ something like 1/3 (?), so boards are available
that plug into the 80287 socket and drive the 80287 at 8mhz (twice the
normal speed) using 8mhz 80287s. [Note: the 80287 is the optional
chip that speeds up floating-point arithmetic.]
100ns RAMs: 128k @ circa $7 each; 256k @ $5.15 each
Software: A patch is available for $24.95 that inserts a floppy drive
timing delay to stop those Drive Not Ready episodes when operating at
> 9mhz. A patch to defeat that rotten timing loop in the new 30MB AT ROM
is also available (isn't life wonderful).
Speed Switches: Several companies are selling switches that let you switch
between 2 to 5 different speeds. (I made my own for < $10). The 2 most
interesting are sold by AMS: The AT-1 lets you switch manually between 3
different speeds for $74.95. The AT-2 @ $124.95, lets you switch between 3
different speeds using the *KEYBOARD*. One or both also contain hardware
and/or software to defeat the timing loop in the new AT ROM. Both come with
a reboot button and *OCCUPY AN EXPANSION SLOT*. (NOTE: Paged memory boards
won't yet run at faster speeds). I'm saving my shekels for the 80386
upgrades/add-ons coming out this year.
In response to my request, Stephen offered the following sources for
the abovementioned products. These are not necessarily the only sources,
but Stephen cites them as ones that solicit retail business. He didn't
give the full names of the companies, and I haven't tried to fill them in.
Fast crystals, 80286s, software patches, 80386 product in near future:
ARIEL, (201-788-2788).
100ns RAMs, 80286s, 80386 Motherboard, RAM boards, software patches.
Will modify your AT motherboard if needed to make it run faster.
BGI, (215-538-3900).
Fast crystals, AT-1 & AT-2 Speed Switches, software patches.
AMS: (818-810-8443).
Speed Switches, Crystals, 8mhz 80287 board, software patches.
Megahertz Corp: (801-355-8857) .
8mhz 80287 board, 8mhz 80287s, Established reliable company. MicroWay:
(617-746-7341).
100ns 256K RAMs. Microprocessors Unlimited: (918-267-4961).
Very cheap crystals with thin wire leads for making your own speed
switch, etc. B.G. Micro: (214-271-5546).
A patch to prevent the timeout Drive Not Ready messages is available
over CompuServe through library DL0 in PCS-131. The name of the file
is FIXDSK.ARC.
A note of my own: the companies I've seen advertising high-speed
crystals are charging $8 to $16. Fry's Electronics in Sunnyvale is
selling 'em for $1.99.