Warframe low fps with good PC specs

[creepyNuts]

Hello guys, I need help if you somehow know how to fix warframe in-game fps, but first of all here are my PC specs:
GPU: R9 280X OC Dual-X Sapphire 3GB Edition
CPU: AMD Athlon II X4 640
RAM: 8GB
Monitor: 1920x1080
So as the title says i have very low fps when playing in missions with party members, it drops like 30 fps but when i play solo its like 60fps with very smooth gameplay. When i am in the ship i have up to 100+fps. On every site on google ive been it says that i can run warframe on max and I do but only when i do mission solo. Please if u can help to ''fix'' this if this is a bug or something not properly set help me because its really getting me off the game that i played over 480hrs.
Ty in advance

[Brujeira]

The graphics routines had a major overhaul a while back so the game probably requires a bit more power from your machine. The thing is that they didn't update the minimum specs on the store page and that's what all those sites you found on Google are using to figure out what settings you can run it at. No wonder they're overestimating your machine's capabilities.

To be honest, turning the settings down may be your only option. While your graphics card looks half-decent, it's paired with a 7 year old CPU - and not a particularly good one at that. Time for an upgrade?

[Forcen]

You can test your PC here and link the results for some more comparisons: http://www.userbenchmark.com/