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NeXT-FAQ.memory: NeXT memory


*** Subject: R1. What type of memory may be installed in a NeXT?

[See also NeXTanswers' hardware.620, and "Announcing NeXTstation Turbo and
NeXTcube Turbo" in 92_spring_bulletin]

Remember, RAM replacement voids the warranty on the older products, but is
"allowed" for the Turbo and newer 25-MHz systems. 


NeXT Computer (68030-25MHz/68040-25MHz),
NeXTcube (68040-25MHz):

Cubes have 16 SIMM slots.  SIMMs must be installed in groups of 4 in these
machines. 

Use low-profile 30-pin 1 or 4 MB SIMMs with 100 ns minimum access time.  The
low-profile vertically mounted 4 MB SIMMs are easier to install in the
NeXTcube than the horizontally mounted 4 MB SIMMs because of the small height
clearance above the SIMM slots.  It is possible to install the horizontally 
mounted 4 MB SIMMs, but you will be required to slide the CPU board and the  
center
tower in simultaneously.

Parity (9-bit) SIMMs can be used in both 68030 and 68040 NeXT machines, but
should not be mixed with non-parity SIMMs. Only 68040 boards with ROM levels of
2.2 (v63) and higher can use the parity memory to detect parity errors. 


One user adds the following unverified claims:

[It is OK to mix parity and non-parity memory, but the system will not boot
unattended. Cubes with early boot ROMs will not work with 4 Mb parity ram,
unless at least 3 banks are used.  The system gives an exception error on power
up. The fix is to get a new boot rom from Next.  You can pay $30, or you may be  
able to
squawk and get one for free.  I have found Next to be pretty responsive, once I
find the right person.]  


NeXTdimension boards (i860):

These boards have 8 SIMM slots. SIMMs must be installed in groups of four on  
the
NeXTdimension board.

Use 72-pin 1, 4, or 8 MB SIMMs with 80 ns or faster access time.  The SIMMs are
organized 256Kx32 or 1Mx32 for non-parity systems, and 256Kx36 and 1Mx36 for
parity.


NeXTstation (68040-25MHz),
NeXTstation Color (68040-25MHz) (older styles):  

NeXT manufacturing introduced the new 25 MHz NeXTstation CPU board into 
production in late June. To verify which SIMM type your machine uses, check the
system's memory configuration. You can do this by using the ROM monitor s
print memory configuration command m. Start with your machine powered down.
Press the Power key to power on. As soon as the message  Testing system... 
disappears, press command-command-tilde (~ on the numeric keyboard). Under
these circumstances, this will access the ROM monitor. In the ROM monitor,
type m and press return. Turbo-designed boards including new 25 MHz
NeXTstations and all Turbo systems will return messages reporting the
memory configuration contained in four sockets (sockets 0 -3); old 25 MHz
boards will return messages for more than four sockets (usually 8).   You can
tell a Turbo-designed board, and the accompanying 72 pin, 70 nanosecond
SIMMs, by the fact it only reports information for only four sockets. 

Older NeXTstations have 8 SIMM slots. SIMMs must be installed in groups of 4 in
these machines. Use 30-pin 1 or 4 MB SIMMs with 100 ns minimum access time.  

Older NeXTstation Colors have 8 SIMM slots. SIMMs must be installed in groups
of two. Use 72-pin 1 or 4 MB SIMMs with 80 ns or faster access time.  The SIMMs  
are
organized 256Kx32 or 1Mx32 for non-parity systems, and 256Kx36 and 1Mx36 for
parity.   


NeXTcube Turbo (68040-33MHz),
NeXTstation Turbo (68040-33MHz),
NeXTstation Color Turbo (68040-33MHz),
newer NeXTstations (68040-25MHz),
newer NeXTstation Color (68040-25MHz):   

These systems have only 4 SIMM slots, but they can take double-sided SIMMs. 
SIMMs must be installed in groups of two in these machines.

Use 72-pin 4, 8, 16, or 32 MB SIMMs with 100 ns minimum access time. For  
maximum
performance use 70 ns SIMMs.  


[John Graves, Hardware Engineering, NeXT Computer, Inc. adds]

The memory system has programmable memory timing such that the number of
processor clocks needed to access a given amount of data can be tailored to the
speed of the memory installed. 70 ns memory is just enough faster than 80 ns
memory to allow the cpu to access the data with fewer clock cycles. This
improves memory system performance.

"70 ns" memory is faster than "80 ns" memory in many parameters other than just
RAS access time. The faster CAS access time in particular allows the memory
system to respond quicker to burst (16 bytes) bus transfers. 

____________________________________________________________________________

*** Subject: R2. What is the NeXT SIMM tool?

The tool came with 68040 upgrade kits for NeXTcubes.

It really makes removing SIMMs easy.  It looks like a dental tool: about six
inches long with a 1/2" long head offset at 90 degrees.  To remove SIMMs, you  
slip
the head into the hole on one side of the SIMM, rest the head on the SIMM  
socket
next to the SIMM you are pulling, and pivot the tool back, using the simple
fulcrum to gently pry the SIMM up about 1/8" from the socket on that side.   
Repeat
on the other side, and the SIMM can be then removed by hand. 

____________________________________________________________________________

*** Subject: R3. Where can I purchase memory for a NeXT?

This list does not necessarily contain all vendors. Suggestions for
additional vendors welcome! 


*** PRICES ARE CHANGING DAILY ***


South Coast Electronics
Tustin, CA
(800) 289-8801
714-669-9503
Contact: Jim

[Prices current as of 12-Nov-92]

30 Pin SIMMs
1x8-80ns	 1 Mb SIMM   $ 38/44(PO Price)
4x8-80ns	 4 Mb SIMM   $152/175

72 Pin SIMMs
8 MB Kit		(non parity)	$320/369
16 MB Kit	(non parity)	$640/738
32 MB Kit	(non parity)	call for price

8 MB Kit		(parity)	$360/415
16 MB Kit	(parity)	$733/846
32 MB Kit	(parity)	call for price

MC/Visa same as cash, Purchase Orders more.


Impediment

(617) 837-8877
Contact: Alex

[Prices current as of 11-Aug-92]

30 Pin SIMMs
1x8-80ns	 1 Mb SIMM   $ *
4x8-80ns	 4 Mb SIMM   $ *

72 Pin SIMMs
1x32-80ns	 4 Mb SIMM   $ *
1x32-70ns	 4 Mb SIMM   $ *
2x32-80ns	 8 Mb SIMM   $ *
2x32-70ns	 8 Mb SIMM   $ *

* Refused to give pricing!  Also has parity SIMMs.


Stratum Technologies
Austin, TX
800-533-1744
512-258-3570
Contact: Ted, Mike 

[Prices current as of 12-Nov-92]

30 Pin SIMMs
1x8-80ns     1 Mb SIMM   $ 34
(1x8-60ns in lots over 100 $30)
4x8-80ns     4 Mb SIMM   $ 118

1x9-80ns     1 Mb SIMM   $38
4x9-80ns     4 Mb SIMM   $140

72 Pin SIMMs
1x32-70ns	 4 Mb SIMM	$122
2x32-70ns	 8 Mb SIMM	$245
4x32-70ns	16 Mb SIMM	$550

1x36-70ns	 4 Mb SIMM	$142
2x36-70ns	 8 Mb SIMM	$280
4x36-70ns	16 Mb SIMM	$625

Lifetime Warranty.


Marco International

800-621-4668 (Within US/Canada)
303-449-9191 
Contact: Lisa

[Prices current as of 12-Nov-92]

30 Pin SIMMs
1x8-80ns	 1 Mb SIMM	$ 36
4x8-80ns	 4 Mb SIMM	$ 122

72 Pin SIMMs
1x32-80ns	 4 Mb SIMM	$129
1x32-70ns	 4 Mb SIMM	$129
2x32-80ns	 8 Mb SIMM	$256
2x32-70ns	 8 Mb SIMM	$256
4x36-70ns	16 Mb SIMM	$530

Parity also available.
Lifetime Warranty, toll-free support, 24hr RMA.


Chip Merchant
9541 Ridgehaven Court
San Diego, CA 92123
(800) 426-6375


____________________________________________________________________________

NeXT-FAQ Editor:
Nathan Janette nathan@laplace.csb.yale.edu


--
Nathan Janette		"I'm a NeXTstep man,
Dept MB&B, Yale Univ	 I'm a NeXTcube guy"
New Haven, CT
nathan@laplace.biology.yale.edu (NeXT)