I have just tried to upgrade a ICL / Fujitsu Series-D system (1995) which has 2 x 4mb of EDO RAM. The system support 64MB of RAM acording to the Manufacturer but when I install 2 x 16MB or 4 x 16MB the system runs a memory check ok but Windows/95 does not start. Leaving the 2 x 4 MB in place and adding 2 x 16MB the system sees 40MB, memory test runs ok, Windows / 95 starts but restarts before program load completes. Any ideas? The 4MB RAM are HYM532100AM-70 and the Motherboard is set to 50Mhz by jumper. My 16MB SIMMS work fine in another system set to 66Mhz. The Bios is ACER, should I upgrade it?? Thanks and regards. Terry

Are they all EDO? I'll bet your system only accepts EDO.

Your 4Mb sounds is probably Fast Page Mode memory rather than EDO as it is 70 nanosecond memory and EDO is 60 nanosecond. Divide 64 by the number of memory slots on motherboard to determine maximum size SIMM that will work. Newer memory may not work. Do not overclock processor.

Are they matched sets? Or are they mixed? parity or non parity,EEC or FPM.And what does the motherboard require?If the original are 70ns are they also parity?If you mix non-parity with parity; the parity will not function.Unlike using 70ns in bank 0 and 60ns in bank 1 which works fine in most systems.Or FPM in one bank and EDO in another.(this works in my old thousandoaks board at least.)

Check your manual or manufacturers site for valid combinations of memory. Some older machines were fussy about the size and slot placement of memory. There may be jumpers on the motherboard also.

Thanks for the help so far. The 4 x 16MB SIMMs are M5M417405CJ Misubishi and have 8 chips on the SIMM. What type of EDO are they and are they compatible with the YM532100AM-70 that is already installed? I have tried them with and without the 4MB. With the 4 x 16MB installed the system recognises 64MB but doesn't boot to win/95. Any suggestions. Here are the specs from the manufacturer manual. The only jumpers on the board that seem relevant are bus speed and multiplier ones. Should these be altered? Specifications & Memory tables/D-Series/Memory configurations BANK 1 BANK 2 Total memory SIMM-1 SIMM-2 SIMM-3 SIMM-4 4M 4M - - 8M 8M 8M - - 16M 16M 16M - - 32M 4M 4M 8M 8M 24M 4M 4M 16M 16M 40M 8M 8M 8M 8M 32M 16M 16M 8M 8M 48M 16M 16M 16M 16M 64M SIMM recommendations SIMM size (MB) Description Speed Module code 4 1M*32 70ns AF33270 8 2M*32 70ns AF33277 16 4M*32 70ns AF33271 Regards Terry