From: [email protected] (Dan Smisko)
Newsgroups: comp.sys.apollo,comp.sys.hp.hpux
Subject: Re: Processor Upgrade HP9000/400
Date: 5 Mar 1998 17:39:54 GMT
[...]
040 Clock Jumper (25Mhz versus 33Mhz)
The position that the clock jumper is set in depends upon a couple of
factors. Originally all clock jumpers for 68040 @ 25Mhz SPUs were
set to the 33Mhz position to allow proper memory - CPU chip operation.
The memory controller chip code has been modified to allow the 68040
processor to operate with the clock jumper in the designed position.
Please follow the matrix below:
SPU New Board Generic Exchange Memory Controller
Board Chip Location
375 98574-63510 98574-69510 U21
380 98574-63511 98574-69510 U21
400t A1630-66001 A1630-69001 U14
425t A1630-66013 A1630-69001 U14
400s A1421-63510 A1421-69510 U56
425s A1421-63513 A1421-69510 U56
If the label on the chip is 1LY3-0302, put clock jumper to 33Mhz.
If the label on the chip is 1LY3-0304, put clock jumper to 25Mhz
for 040 CPU's running at 25Mhz.
--
33Mhz machines will be in the 33 position.
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Dan Smisko
I have the 1LY3-0302 chips, but haven't noticed any difference between the 33 and the 25 jumper settings. Supposedly it adds a wait-state if it's in 33 MHz mode, but maybe my benchmark programs fit into the L1 cache (doubtful).