When downloading or seeding, you may want to adjust the FrostWire transfer parameters to accomplish certain goals. The basic tools to do this are all on the Tools>Options/Bittorent/advanced menu.
When downloading, I've noticed that too great of an up load speed will compromise download speed. For optimum downloading, you will want to set download speed at or near your maximum line speed. If you, or anyone else on your network, wish to access other internet services, 80% of your maximum speed may be advisable. At the same time, setting your upload speed to 35% of upload maximum seems to allow adequate downloading to occurs. Running upload at maximum does seem to impact download speed. Many people will notice that their upload speed is about 1/3 of their download speed, and I'm recommending using 1/3 of that for optimum downloading.
It is good to limit the number of download torrents to a fairly small number, so that they can complete, be used, and be shared fully. You will want to consider the number of peers that you allow to each torrent. Too low of a number will may not allow you to reach line speed, while too many will add to system overhead and not be useful. I would use no less than 10 and no more than 75 for downloading. The precise value depends on run time availability and cannot be predetermined.
If all you're doing is seeding, totally different parameters will optimize seeding performance. You need to decide it you want to give a little to a lot of people, or a lot to a few people. I prefer the latter, and that approach seems to limit the load on my machine.
To accomplish this I will open my upload speed to about 85% of my maximum up load rate. This allows other process to get data up-line!!!! If you want to access a forum, read email or chat, you do need some upload capacity left. Limit connected peer per torrent to around 2 to 4. To many and you'll not be providing higher speed data to every one, but a slower stream to many. The seeds column on the transfer window can give you some clues, here.
So far, I've not mentioned global maximum number of peers connected. Each connected peer requires and represents a connection, but remember that connections are a pool. If all torrents have maximum connections, the number of torrents that can be connected can be calculated by dividing max connections by max number of peers per torrent. However, since not all torrents may have that many seeds, that is a theoretical number, only, but it's a good starting point.
If you find that you're not reaching your upload target speed, you will have to need to increase the values. The transfer window will help. Check upload speed and peers. If there are peers that are not connected due to the maximum number of peers, increase it. You can also increase number of upload slots per torrent to increase upload speed, but if you are dealing with sparsely requested torrents, that won't help.
I'm sharing at 250/10/4. I'm reaching line speed with six connected torrents with decent upload speed per torrent for my line. My numbers may not even be close for you, but if you do the math and experiment, you can hit the right combination in a few minutes.
There is a nice freeware program that will allow you to monitor and track line speed. Free is good! http://www.softperfect.com/products/networx/
And here where you can determine your line speed. http://www.speedtest.net/