Re: 7011-220 performances

supervinx wrote:
Hi !
Yes, the 220 is a bit slow, but is faster, compared with a 33 MHz PC clone ...
This is due to:
1) RISC (and not CISC) architecture
2) IBM architecture
3) AIX
4) Graphic card

I accept suggestions ...

Hi Vinvenco,

1) the POWER RISC is superscalar, i.e. it can execute multiple instructions at once, and being RISC, integer instructions only take a single clock cycle
The 386 needed multiple clocks per instruction, the 486 had the most common instructions reduced to a single cycle as well. The pentium was the first x86 to go parallel internally, but many instructions wouldn't allow this parallellism. The Pentium PRO could easily be cripled by executing a lot of 16 bit instructions, segment operatons would almost freeze it.
The cache of the RISC is most likely bigger than what the x86 had to offer at that time.
For floating point instructions, there is still no contest looking at the POWER processors (unless you start adding GPUs to the mix).

2) I expect that the memory subsystem was faster and wider than the typical AT. I/O might have given mixed effects (ISA, EISA, VLB, PCI vs. streaming accesses and possibly split MCA buses).
Most likely, you are also comparing a simple IDE drive with a decent SCSI one. Big difference at that time.

3) I would expect DOS/Win to be lighter to run than CDE layered on X layered on AIX. Ample memory did help AIX (file caching).

4) The memory bandwidth towards the adapter is a first point to consider and next, an advanced graphics card can help the CPU a lot, assuming the graphic routines use it.

I hope I didn't make too much mistakes.

Regards,
Alvin.

PS. I noted that you're aiming at the swiss LX40?
.

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