Six PostgreSQL questions from a pokerplayer

I use poker software (HoldemManager) to keep track of the statistics (and
show nice graphs) of millions of poker hand histories.
This software (also PokerTracker 3) imports all the poker hands in
PostgreSQL. The software runs on Windows) only.
All of its users have NORMAL PCs. From single-core laptops, to a quadcore
desktop at best.

Questions:

-1 [quote] "POSTGRESQL uses a multi-process model. Because of this, all
multi-cpu operating systems can spread multiple database connections among
the available CPUs.
However, if only a single database connection is active, it can only use one
CPU. POSTGRESQL does not use multi-threading to allow a single process to
use multiple CPUs."[/quote]

I can see two databases in my pgAdmin: postgres and HoldemManager. All the
poker data (about 30 GB of data) is in the HoldemManager database.
Does the quote above (if true?) means, having a 2 Ghz single core or a Xeon
2x quadcore (8x 2 Ghz cores) will make no real difference for my
performance?
And the real performance increase is only for professional servers running
multiple databases? Will I greatly benefit from having quad instead of a
single-core system?

-2 In the recent 8.3 vs 8.4 benchmarks, 8.4. was much faster than 8.3
running on a 16 and 32 core server (with 64GB RAM).
With 8 cores, they were about the same speed. Does this mean on a normal
single core computer, there will be NO NOTICABLE performance increase in 8.3
vs 8.4 and even 8.2?

-3 [quote] "With PostgreSQL, you could easily have more than 1GB per backend
(if necessary) without running out of memory, which significantly pushes
away the point when you need to go to 64-bit.
In some cases it may actually be better to run a 32-bit build of PostgreSQL
to reduce memory usage. In a 64-bit server, every pointer and every integer
will take twice as much space as in a 32bit server. That overhead can be
significant, and is most likely unnecessary." [/quote]

I have no idea what the maximum amount of RAM is, my database uses. But what
exactly "will take twice as much space"?
Does this mean a simple database uses double the amount of RAM on a 64 bit
system? And it's probably better for my 30 GB database to
run a 32-bit build of PostgreSQL to reduce memory usage?

-4 One a scale from 1 to 10, how significant are the following on
performance increase:
-[ ] Getting a faster harddisk (RAID or a SSD)
-[ ] Getting a faster CPU
-[ ] Upgrading PostgreSQL (8.2 and 8.3) to 8.4
-[ ] Tweaking PostgreSQL (increasing # shared_buffers, wal_buffers,
effective_cache_size, etc.)
-[10!] Something else?
-[ ] Does NOT effect me, but I was wondering what a switch from Windows to
LINUX/Solaris does for professional server users in terms of performance.

-5 The IO operations/s performance of your harddisk vs read/write speeds vs
access time? What is more important?
With 4 regular harddisks in RAID0 you get great read/write speeds, but the
SSDs excel in IO/s and a 0.1ms access time.
What is the most usefull for which situations?

-6 The 8.4.0-1 one-click installer automatically set the encoding to UTF8.
With the other installers, I was able to
change the encoding to SQL_ASCII during the installation process. How do I
solve this after I've installed 8.4.0-1?
(I was unable to delete the postgres database, so I couldn't create a new
one with the right encoding in 8.4.0-1)
--
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