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Subject: Re: Millennium system questions

Author: Ratko V Tomic

Date: 00:57:30 11/26/99

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> BTW, is it true that a program written in 32 Bits is 2x faster
> than the same program writing in 16 Bits?

If the main program (GUI) which runs the engine is a 32 bit code then
the 16 bit engine is somewhat slower (perhaps 10-15 percent) than
the same 16-bit engine compiled to run in the 16-bit GUI. On the other
hand, if a 16-bit GUI were to run a 32 bit engine, then this engine
would run slower than the same engine in the 32 bit GUI. The reason
for all of this is a peculiarity of the Intel CPUs, where the main
executable environment (32 bit or 16 bit, as defined by GUI) defines
which operations (16 or 32 bit) are default, thus which use fewer
bytes per instruction and fewer CPU clocks. If GUI is 16 bit, the 16
bit instructions in the engine are quicker, if GUI is 32 bit, the 32
bit instructions in the engine are quicker. The mixed situation is
always worse.

As to how much would a 32-bit engine (running in the 32-bit GUI) be faster
than the 16-bit engine (in the 16-bit GUI), that certainly wouldn't be a
factor of 2, but much less (probably no more than 20 percent faster,
depending on the type of algorithms used, mostly on whether the move
generator uses the bitmaps, which would be the best case for the
32-bit program; otherwise there may be no noticable speedup at all).




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