Attached Link: 18004memory

I see that **inshaala** refined his PC upgrade questions by asking,

does it matter what type of RAM?
memory and is faster ... better when running ... photoshop

The motherboard and processor (CPU) determine the correct memory
speed/timing.  You'll need to know the exact motherboard model number
and that will determine the correct memory. 

That having been said, you may have a choice on one memory timing
parameter ... 'CL' (it's how fast the memory responds).  You may see,
CL2, CL2.5, or CL3 -- although the smaller number is better (faster),
you should match the speed of the existing memory stick ... or replace
it by buying 2 identical sticks. 

When you know the motherboard manufacturer and model number, use
the Memory configurator on 18004memory web site. 

I am running a backup system anyway

In a sense, RAID is not a backup system -- a RAID array seamlessly
overcomes the failure of one drive in the array ... until you can replace
that drive. 

OTOH, a backup system (or an archiving system) stores extra copies
of your information offline from the PC so that the data can not be lost.  

RAID protects you from the risk of a HDD failure -- and provides a
performance boost in some configurations.  

A UPS protects you from a short power failure (3 to 5 minutes)

A standby generator by itself protects you from a longer power outage
... but not from the loss of power. 

A standby generator with a UPS protects you from short and long power
outages. 

A backup strategy protects you from the risk of fire, theft, accidental file
deletion, virus activity, mechanical damage, etc. ... but doesn't protect
your work in process. 

have a WD 500Gig MyBook

Actually, you should have 2 of those external drives -- you could put the
same backup set on each ... or use them on a rotating basis.  "Why?" you
say ... suppose something went wrong during the backup to a single drive,
you could loose everything.  OTOH, with 2 backup drives, you would still
have the alternate backup set.  Archiving to CD (or DVD) is a partial
solution to that point ... provided that you always take the time to make
the extra and identical copies. 

HTH but always remember that YMMV

--
Martin