Path: utzoo!attcan!uunet!snorkelwacker!mit-eddie!uw-beaver!rice!solomon
From: solomon@rice.edu (Richard L. Solomon)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Everex RAM-3000 Deluxe Failures
Summary: blame MB, not Everex;  Everex good.
Keywords: MotherBoard problem Everex good
Message-ID: <5357@brazos.Rice.edu>
Date: 28 Feb 90 15:25:14 GMT
References: <6846@ubc-cs.UUCP> <1990Feb28.033007.16273@sj.ate.slb.com>
Sender: root@rice.edu
Reply-To: solomon@screech.rice.edu (Richard L. Solomon)
Organization: Rice University, Houston, Texas
Lines: 54

In article <1990Feb28.033007.16273@sj.ate.slb.com> poffen@sj.ate.slb.com (Russ Poffenberger) writes:
>In article <6846@ubc-cs.UUCP> jalbert@cs.ubc.ca (Francois Jalbert) writes:
>>About a month ago, I bought an Everex RAM-3000 Deluxe (EV159), put 3 Mb on it as
>>extended using 100ns memory chips, left the W1 jumper on it for 2 wait states,
>>and tried it on my 14/9 MHz 80286. All worked fine so I bought it. Now, after
>>5 weeks of use, the Everex is failing. Certain rows and columns of the
>>matrix of memory chips fail. Swapping/replacing memory chips doesn't help.
>>The board works fine in the 12/8 MHz 80286 of a friend though. The newly found
>>problem is obviously linked to the bus speed. However, nowhere in the 
>>documentation is a possible bus speed limit mentioned. Of course, I had checked
>>thoroughly for such a potential limitation in the documentation before buying.

	Officially, (As in Big Blue's dictum and the ISA spec portion of EISA)
the AT (ISA) bus is limited to 8MHz.  After working tech support for a shop
that sold numerous clones, I feel qualified to throw in some thoughts here. 
Most clone MBs do a lousy job of decoupling the CPU speed from the bus speed.
Instead of running the two asynchronously, they try inserting wait states
or doing less kosher things like playing with the system clock during bus
accesses.  Admittedly, Everex should be aware if their boards have some
dependency on clock speed or whatever, BUT there is an incredible difference
in how different MBs violate spec.  Some clone MBs will actually work better
if their bus-limiting stuff is turned off (a few MBs have a jumper to allow
running the bus at full-speed.)  
	In order to save money, clones sacrifice technical sophistication.
When you buy a no-name clone, be careful.  I recommend clones highly, but
I also recommend buying a name if you want more than 10MHz.  We had tons and
tons of trouble with 12MHz clones.  Apparently the newer 12's run Ok, as long
as the on-board DRAMs are a little faster than the docs request.  A good
(Everex, NEC, AST, Compaq, etc....) well-engineered MB runs the CPU at
one speed and the bus at another.  Cheap MBs try this, but rarely pull it off.

 
>>P.S. I won't touch an Everex product for the rest of my life!

	I'm sorry to hear this, I am in no way affiliated with Everex, but have
found their products to be generally high-quality and well-engineered.

>I had a similar problem with an EV-159. I bought it, took it home and put it in
>my 16/8 Mhz '286 clone and would get all kinds of strange results. I took it
> 
> [stuff deleted]
>
>As far as not buying another Everex product, I don't know, I also have a 2400
>Baud modem, magic I/O card, and tape backup, all from Everex and have never
>had any problems with those.

	Everex modems are amongst the best, ditto for tape backups, I have no
experience with their I/O cards.

	Again, I have no affiliation with Everex other than as a satisfied
customer.
 
Richard Solomon
solomon@owlnet.rice.edu