Windows 10: GT 710 with 2 GB of DDR3 or 1 GB of DDR5?

Which do you think is better?

This GT 710 with 2 GB of DDR3 (64 bit)

or

this GT 710 with 1 GB of GDDR5 (32 bit)

keeping in mind I don't game, but watch a lot of 1080p video and have 100s of tabs open at a time in Firefox.

My computer:
CPU: Athlon II X2 250 3.00 GHz
MB: Don't know
RAM: 8 GB DDR3

 

8 gb of ram in pc, only 4 gb visible

I have 2 sticks of 4 gb DDR3 RAM in my pc, and there hasn't been anything yet. But suddenly, my pc started lagging, and I found out that the pc only uses 4 gb. The 2 sticks are visible in bios, but nowhere else.

 

Will 8 GB make WIN10 run ok on a Core 2 Duo?

Microsoft lists the Windows 10 minimum hardware requirements as:

• Processor: 1 gigahertz (GHz) or faster processor or SoC.
• RAM: 1 gigabyte (GB) for 32-bit or 2 GB for 64-bit.
• Hard disk space: 16 GB for 32-bit OS 20 GB for 64-bit OS.
• Graphics card: DirectX 9 or later with WDDM 1.0 driver.
• Display: 800x600

But I reccomend

1. processor: 2.5 GHz Dual Core (Faster is better)
2. RAM :- 4 GB (2018 Atleast 8 GB)
3. HDD 320GB
4. GPU :- any (Nvidia Tiatan v is the Best)
5. Display :- 1920X1080 (Full HD)

 

2.5 GB usable out of 4 GB of ram

I have a HP pavilion g6 1301tx laptop. It came up with 2GB of DDR3 ram, windows 7 pro (64 bit), 1 GB ATI graphic card and motherboard - hp 1670 serial number- pcela212c1bo7I. Few months back I installed Windows 10 (32 bit) . Now I want to increase ram by 2 GB , total of 4 GB so I installed a 2 GB DDR3 ram to the other slot and checked system properties of my computer it says 2.5 GB usable out of 4 GB, now I don't understand why rest of the 1.5 GB is not usable what should i do to get 4 GB ram?