It is just you. Or, it is everybody, but its just you in this case, therefore its just this case.
The way this works is the server has slots to upload, and some of them are either exhausted or not that good to begin with. You get a slot assigned when you start uploading, and you can get a great deal of bad luck in getting the bad ones repeatedly.
In my experience i get about 4-5:1 in bad vs good slots, where the bad ones average at 300 kbs and the good ones at 3mbs.
Using more slots is a good way to even the odds this way. I use 8 and my average uploading speed for the whole uploading batches is 5-7 mbs.
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Added after 36 minutes:
by more slots you mean uploading multi files simultaneously right??
Zoom uploader is a wonderful, very versatile tool. You can use 8 slots in the "trial" version, and you are not limited in the full one. Knowing how the slots work, you can experiment yourself and devise your own way.
If you have bigger batches of content, you can let them upload all at once (assuming you are not wasting _that_ much more system resources, being limited by a certain speed) and then re-start your uploads, when you see them get assinged a bad slot.
With less content you can go the way starting multiple uploads of the same file and doing the same.
But what i would advise to, and this is my opinion, is patience. I see you are using content that is not time sensitive, and you also diferentiate in providers. Therefore, the best way to go for you would be actually just having datacloud (or either slower service) processes run on the background while working elsewhere, and then return to a done deal and process it in bulk.