HD4850, stick or twist?

[stree]

Not that savvy with graphics, so any help appreciated.
Overview:
MB ASrock H97M-ITX/ac BIOS is latest 1.8
G3258K @ stock (Going to try a modest OC sometime)
8GB HyperX fury ( 2x4)
Win7 x64 Pro.
GPU is Intel on a chip basic, with latest drivers etc.
I use mainly for movies, light Photoshop, occasional light gaming, some photo editing. No real gaming needs to consider.
One thing is important and that is a quiet system, which it is right now.
For that reason I am using a 160W Pico PSU, but I do have a Seasonic M1211 I can use instead.
First question relates to DirectX. I ran dxdiag and seems I have 11 on board ( I thought it came on the GPU so maybe it`s on the G3258?) Is that so?

Second, I do have an old GPU I am tempted to use just because it seems a better option than the onboard Intel.
Gigabyte Radeon 8450 Passive 1GB.
This is ratted at 110w TDP so I would use the Seasonic ATX PSU . Just looked and it1s the Bronze EVO one @520w
This GPU is Directx10, would that make any difference in terms of my usage?
In other words, is it worth installing this card?

 

[pandem0nium]

The 4850 only supports DX10, not 11. The pentium has an IGP that supports DX11 but you won't be using that while gaming.

The 8450 is going to be worse than the 4850 you have installed.

 

[stree]

Whoops. Typo by me Only one GPU and it is the 4850.................No 8450 involved here.
Sorry about that confusion.
and I did say, the GPU is DX10, I am aware of that , I just named the card wrongly.
Anyway, the question remains, I have NO card installed, just the Intel on board graphics, would it be worth using my 4850 card?
Thanks for the quick response by the way, appreciated.

 

[pandem0nium]

No probs

The 4850 would be much better than the igp for games, but you won't be able to play any DX11-only games.