MWL,
You left off the "when lots of other players are nearby" that you had in your first post in the help forum. One of the big offenders now is other players' skins. There are more skins than you have memory to pre-load them so they have to load whenever you encounter a new one. If you have downloaded all the skins and are allowing them to show up, this could cause the problem. A quick check can be done by going to OPTIONS>GRAPHIC DETAIL and put click on the DISABLE OTHER PLAYERS SKINS. If this solves the stuttering problem, you have identified the cause.
If this is the cause, you have 3 options for correcting it. The first is leave the DISABLE OTHER PLAYERS SKINS checked. This means you will always see only the default skin on other planes. Not a big deal since you rarely get close enough to see other skins. On your plane, you will continue to see whatever skin you have selected.
The second way is to have only certain skins available. Use this option if it's important to see specific skins like your squad skins when you up or do formation flying. To do this, you need to delete all the skins you don't want to see, leaving only the ones you do want to see. I believe you will also need to either empty your CACHE folder and let it rebuild or delete the the specific skins folders out of your cache folder. If you choose the second option, it is important that you know which folders to keep and which to delete. These will correspond with the file name of the skins you deleted or kept in the skins folder. Once this is done, you uncheck the DISABLE OTHER PLAYERS SKINS. Players flying the skins you have will show up in them. All others will appear as the default.
The third option is the most complicated. In this option, you substitute the skins you want to see for the default skins in the STDSHAPES folder in the CACHE folder of your main game folder. To do this, you replace the corresponding .TCA files in the STDSHAPES folder with the .TCA files from the skins you want to use. This makes them show up as the default. Then disable all the other skins and you should be ok. Be aware, though, that most of the player built skins are significantly larger files than the default ones so you could still end up with stutters if they are too large to pre-load into memory.
Regards,
Hammer