Upgrading computer-compability questions

[UtaChan]

Ok the idea is to upgrade the HD and memory without upgrading my mobo (hopefully)
I currently have 2 memory sticks both same company but different models (I think) but rest is the same they are 1333.

things I wanna check compability with (things I have):
my graphic card is radeon 5770HD.
My cpu is phenomII dual.
mobo:GA-880GM-UD2H (rev. 1.3)
link for mobo:
http://www.gigabyte.com/products/product-page.aspx?pid=3475#ov
system:win7 32 bit (rather not change to 64)

Things I want to upgrade to:
memory:2x kingston ddr3 khx1600c9d3k2/4gx
link for memory:
http://www.ec.kingston.com/ecom/configurator_new/partsinfo.asp?root=&LinkBack=&ktcpartno=KHX1600C9D3K2/4GX&id=2

HD:
western digital blue wd10ezex
http://www.wdc.com/global/products/specs/?driveID=1092&language=1
OR
Seagate Barracuda st1000dm003
http://www.seagate.com/internal-hard-drives/desktop-hard-drives/desktop-hdd/?sku=ST1000DM003
(is there a difference? if there is which 1 concidered better?)

[side questions]:
What is the difference between the blue memo slots and the gray(offwhite) ones on the mobo?
can I stay with my 32 bit system and still upgrade to the the memo sticks I specified? and are they compatible with my mobo?
Waht is the difference between dimm3 and dimm4? only speed?

Could this work out?

[offtopic questions]:
I am willing to buy external drives which 1 is concidered better:

seagate expansion desktop stbv2000200
http://www.seagate.com/external-hard-drives/desktop-hard-drives/expansion-hard-drive/?sku=STBV2000200

or

western digital my book essential wdbacw0020hbk
http://www.wdc.com/global/products/specs/?driveID=885&language=1
I read it makes troubles but since I don't trust the source I wanted to ask here.

what is the difference between old memo sticks I have:
kvr 1333 d3n9/2g and kvr 1333 d3n9/2g-sp (1 has "sp" and other doesn't)
what is the difference? can they work together to enhance the performance (I think I read something about them being able to enhance performance by working together as a special feature)...it doesn't matter since I upgrade them but I am still willing to know

[Rik_]

Upgrading ram will make no difference to what windows 7 version you have (apart from speeding it up obviously), it's the CPU that can sometimes make a difference. Your CPU is a 64 bit one so it is capable of running both 32bit and 64bit.
Things to bear in mind tho, win7 32bit can only properly handle upto around 3.5gig of ram including graphics ram. Win7 64bit can handle a lot more. I forget the maximum limit for win7 64bit but it's in the region of 32gb I think.

Those hard drives should be almost identical on speed as their stats are almost identical.

My advice would be to stick to internal drives unless you absolutely need portability. It's almost impossible to drop and destroy an internal hard drive, they also stay a lot cooler than externals too.

[caperjack]

system:win7 32 bit (rather not change to 64)

i suggest you retink this, to get the full potential of your computers hardware ,ie:its 64bit cpu and the ability to utilize a lot more ram .it would make for a much better computer for you . remember that most 32bit app will work with 64bit if thats you concern

[Rik_]

Just had a good google and win7 64bit can use upto 128gb of ram. Upgrading to 4gb of ram with win7 32bit means you'd have half a gig that is completely unusable.

[caperjack]

Just had a good google and win7 64bit can use upto 128gb of ram

as long as you motherboard supports that much also .its likely all newer ones do now