On 12 Aug 98 at 19:19, Ahmed Hassan wrote:

> is there are 2 types of socket 7? what does it means that the
> motherboard is dual voltage?
> and How I know if the motherboard is dual Voltage?

  "Socket 7" refers to the physical socket itself, and which
signals/power are routed to what pins.  There are two "types" -- on
one, the lever is plastic, and on the other, it's metal -- but it
makes no difference which type a board uses.

  Dual-voltage support is generally a feature of the motherboard
itself, not the socket.  The socket provides a number of "power"
pins; a dual-voltage board is able to supply a some of those (very
specifically) with one voltage, and the rest with another.

  You may still find some boards which don't offer dual-voltage
support, but these should be rare because there are few CPUs still
being made that don't need it.  You're most likely to have to check
this out if you're looking to upgrade an older board.
  If you can find, on the board or on its maker's web site, any claim
of "P55C" compatibility, then it definitely offers dual-voltage, at
least for the most common settings.
  There was a period when many inexpensive boards (primarily using
Intel 403VX chipset, I think) were equipped with a connector for a
VRM (Voltage Regulator Module).  The idea was that the board shipped
with a few jumpers to supply the same voltage to all power pins, but
you could remove the jumpers and add the VRM to supply reduced core
voltage[*].  Unfortunately, while there appears to have been
agreement on the shape/size of the connector, the add-ons themselves
were claimed to be board-specific.  Finding one now for a board that
was bought two years ago is going to be hard.

  There is a company called PowerLeap, who make a device called
PowerStacker, which sits between the CPU and the socket.  It provides
dual-voltage support on boards that aren't already equipped for it,
and provides extra multiplier settings that weren't provided on some
of the early boards.
  I think it costs about $50; my latest motherboard purchase rab
about $90 and provided other nice features such as SDRAM support.  If
you determine that your board doesn't provide dual-voltage, replacing
the board MAY be a more cost-effective upgrade than the PowerStacker.

[*] Parts of the CPU that send signals to other pieces of the system
need power at the appropriate voltage, usually 3.3v.  Parts of the
CPU that don't need to do that -- about 90% of the chip, according to
Intel -- can run faster, cooler, and with less power consumption, at
about 2.8-2.9v.  On some specific chips, this "core" voltage could be
specified as high as 3.1v or as low as 2.1v.  A dual-voltage
motherboard can continue to work with single-voltage CPUs by setting
the core voltage to the same 3.3v as the I/O voltage.

David G