SMP CPUs scaling factors (was "what is a flop")

Mikhail Kuzminsky kus at
Mon Jul 23 12:44:16 EDT 2012

According to Franz Marini
> On Tue, 17 Jun 2003, Maurice Hilarius wrote:
> > And I would say dual CPU boards do not sale at a factor of 2:1 over singles.
> > ...
> > As a general ( really general as it changes a lot with code and 
> compilers) 
> > the rule I know :
> > Dual P3 ( VIA chipset): 1.5 : 1
> > Dual XEON P4 ( Intel 7501 chipset): 1.3 : 1
> ... 
> > Dual AthlonMP ( AMD 760MPX chipset) 1.4 : 1
> Does anyone have some real world application figures regarding the 
> performance ratio between single and two-way (and maybe four-way) SMP 
> systems based on the P4 Xeon processor ?
  I may say about SMP speedups for AthlonMP/760MP, for P4 they
will depends from chipset (kind of FSB and memory used). On G98 speedup
for 2 CPUs is between 1.4-1.8 depending from calc. method and problem
size. For Opteron/1.6 Ghz they are higher (up to 1.97 in some G98 tests).
4-way P4 SMP may be not too attractive if 4 CPUs will share common
bus to memory. 4-way Opteron's system must be very good (they may
be will arrive soon in the market).

Mikhail Kuzminsky
Zelinsky Inst. of Organic Chemistry
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