You don't want to have that 8 dmg sword.
Quest this
* Speak with Titus at the 2nd floor of the Alchemy Guild in Bastok Mines, at (L-7). In a cutscene, you will be asked to procure twenty grains of gold dust from Grauberg.
o He will give you the key items Prospector's Pan and Corked Ampoule to do this.
* Make your way to (F-13) at Grauberg (S) to find the Riverbed, a spot in the river that can be targeted.
* Examine it and choose one of the given options to start scooping and how roughly to do it.
* Once you have the 20 grains you will receive the key item: Ampoule of Gold Dust
o If you leave the area before you get the 20 grains, you'll have to start over.
o See the Discussion page for successive methods though it does not matter if you fail to find any gold. You will merely need to try again.
* Return to Titus for another cutscene and your reward.
or if you did the event
If you're not up to the quest and don' thave the event sword, then just use 2 onion swords, butt he 8 dmg sword is gonna get you many less skill ups in the end since you're dealing more damage.
As for how much it woudl reduce damage, not sure if that much. My DMG 3 great sword does 5-8 or 9ish w/o the soup and 3-5 w/ it on.
Acc gear is great, try not to wear anything w/ str tho, but yea, def 8 DMG sword has to go.