Good Day
Please, could you help me?
I have a Blademaster (soldier and nightblade) with two swords.
I have a one-handed sword alone in one of the slots, the other slot is empty. I get 8000 Damage per second (DPS). I add a second one-handed sword (almost same to primary sword ), and the DPS goes down and is now 7500.
Why? DPS should go up, no?
Thank you very much for your help.
To understand what really is, we need to see your build. Can you upload your build here and share the link with us? Preferably with both sword you’re mentioning are equipped.
Maybe the 2nd wpn adds a conversion to a dmg type you’re weak in.
I thought that too but it’s dual sword and probably based on physical damage; how much conversion second one can had to decrease the total dps? It should be more than %20. Which all sword has less I believe.
maybe he or she does not have ability to dual wield weapons or has buttons selected wrong for showing dps on char screen? like if has amarastra blade burst on left click then you get lower because that skill has off hand weapon damage used
To better compare DPS numbers, assign the standard attack (no replacer or other attack skills) to LMB. Like @Ulvar1 mentioned, there are some skills that do not work like a standard attack so the shown DPS might be misleading.
He is playing DW Blademaster, which skill possibly could he be using on lmb 
No idea. There are many skills in the game that do not come from Masteries.
Also I was talking in general terms, not only specific to the OPs build (which we do not know atm other than masteries)
Well we can all do supid things in this game for sure 
I did with my first character. Try Lightning Warder without Wind Devil and Arcane bomb 
Thank you all for answering.
I include screen shots
Both swords are very similar.
The first one shows both swords in the slots. You can see DPS is 7506 and you can see the left weapon.
The second shot shows the second sword.
The third shot shows the DPS without one of the swords with a DPS of 7981. Does not matter which slot it is in.
I want to understand why does it do that?
Can you provide us a grimtools link?
That is because cadence dual wield is sketchy and dps stat in game is not working correctly. Look what happens if you switch left skill to regular attack. And also look on second char stat window for cadence damage when using one versus two weapon
Thank you I will check that. The point of night blade is to have two swords 
There are other ways to have two swords. There are relics and medals that allow that for instance
Really? how? Amazing game, you need a PhD to play at this game
https://www.grimtools.com/db/items/1506
https://www.grimtools.com/db/items/8954
https://www.grimtools.com/db/items/798
https://www.grimtools.com/db/items/1473
https://www.grimtools.com/db/items/1493
https://www.grimtools.com/db/items/1516
https://www.grimtools.com/db/items/13754
https://www.grimtools.com/db/items/13786
https://www.grimtools.com/db/items/13711
https://www.grimtools.com/db/items/12126
https://www.grimtools.com/db/items/12131
some are easy to get like some of the relics (faction shops etc) others are random drops
similar for ranged, no need in being inquisitor to use dual pistol
Just look in grim tools, like search “dual wield” and you get items
Thank you. They are at lvl 94 though
I will need to test that on one of my lvl 100 pure soldier
no there are many that are not level 94 like these
https://www.grimtools.com/db/items/1473 buy from devil cross faction
https://www.grimtools.com/db/items/1493 often sells by hyram in steelclap of you have saved him
