Hey guys, as a serious gamer myself I have tried every gaming recorder out there and I choose bandicam because it doesn't lag like the others and I can fine tune it for my computer.
Here are some things that have helped me. They may or may not help you in your situation but I tried these techniques and they work. If you go to the youtube videos area of this forum you'll see videos I uploaded and you'll find they are smooth and even HD on some of them.
I use an external usb Hard drive and I noticed on short videos the frame rates were great but on longer videos I started having stuttering. I knew this wasn't bandicam's fault as it wasn't lagging on the short videos. After much thought it dawned on me that the FAT file settings on the external usb were different than my hard drive so what was happening is the large video files going on my external usb drive were causing it to lag, not because of bandicam but my FAT file format on the external usb. Solution: All I had to do was go into Bandicam settings under the videos area and you'll notice there is a part where you can stop the recording at a preset time. So instead of having larger files you can make the file only about 5 minutes long so if you do a 15 minute video you will have 3 videos. But the 3 videos are smaller than a few large videos. This helped so much. I get no lag at all throughout the whole game and I am also doing commentary videos and it runs perfect even with my voice in game while playing.
ADDING VOICE and keeping a good FPS
I tweaked another setting. Rather than my voice constantly being recorded during the game I realized I didn't need that since you don't talk throughout the whole game but only on certain moments. Bandicam has a feature to where it will only record when pressing a key on the keyboard and you can assign what key to use. I chose the tab key so when I need to also record voice with game I hold down tab while talking and release when done. This keeps fps high as it doesn't have to constantly be recording voice when not needed. It is also wise to set it this way as to not pick up unnecessary background noise during play like dogs barking or phones ringing etc..
Getting rid of the black bars on the side of videos youtube problem
One of the other issues I had was the videos looked great but when I uploaded them to youtube those dang black bars 1 on each side, appeared on the video. I experimented a bit and found that if I match my monitor settings in bandicam with my actual monitor settings the black bars weren't there. In game I can set it at any resolution I want to improve fps but in Bandicam I set the monitor at my exact setting of my monitor 1366x768 So I get great fps in game as I can set that at whatever I want...but the black bars won't show up as I have the bandicam setting at what my monitor size really is.
Hope you guys find this helpful. Bandicam is the best it's all I use