> I have a spare PC and the motherboard manual for it says that it
> acccepts Pentium P54C/P55C MMX CPUs, AMD K6 CPUs, Cyrix/IBM
> 6x86L/6x86MX (M2) CPUs.
> External clock speed is 50,55,60,66,75,83 MHz.
> The socket is Socket 7 - 321 pin.
Socket 7 boards are still rather popular, and there are several CPUs you
can plug into them. Unfortunately, this one doesn't support 100MHz, so
the fastest Socket-7 processors won't work at their full speed.
Quote:> I realize this motherboard is very old, but will Pentium IIs or K6-2
> CPUs work in this?
Pentium II will not work. PII, PIII and Celerons use completely
different physical interfaces. Either Slot-1 or Socket-370. There's no
way you can make this work on a Socket-7 board.
The K6-2 and K6-3 will work. These are Socket-7 chips. But the faster
models will require a 100MHz bus to run at full speed. Still, there are
models that are meant for a 66MHz clock - which you can support.
You should be able to run a 100MHz chip at 66MHz, but the resulting
speed will be slower than the rating. For example, a 500MHz chip is
meant for a 100MHz bus with a 5x multiplier - if you put it on a 66MHz
bus, you'll get 333MHz. If you can still find a chip seller that sells
a K6-2 that's designed for a 66Mhz bus (I think the last ones made at
this speed were the 333MHz models), you should get one of those and save
yourself some money.
You can also try using a 100MHz chip at the 75MHz or 83MHz speed. If
you do, however, be careful that you don't end up overclocking your PCI
slots. The PCI slots must run at 33MHz or slower. Your board may have
special jumpers to allow this. If it doesn't, then don't try setting
the clock speed to anything faster than 66MHz.
(Note that your BIOS may not recognize an AMD K6-2 or K6-3 chip. It
should still work, but it end up identifying it as something else. You
may be unable to enable/disable some chip-specific features. It might
result in an unstable system, but I think that should be unlikely.)
Of course, everything becomes easier if you decide you want to just
replace the motherboard. Motherboards aren't terribly expensive. You
should be able to get a Super-7 (Socket-7 at 100MHz) board with full
K6-2 and K6-3 support for pretty cheap. Socket-370 boards (for
Celerons) are also pretty inexpensive.
Even a high-end board for a PIII or an AMD Athlon aren't very expensive
compared to the cost of the CPU. (Not counting server-oriented boards
with built-in SCSI, Ethernet and multiple processor sockets. They can
cost more than the price of a processor.)