YES! That's exactly how mine is. Downloads cap out at like, 32KBits per second, but upload is still normal 384 KBits/40'ish KBytes per second. I usually just assume my modem's overheating, but I don't know anymore.
Oh, and Internet operation is still good, unless you attempt to receive a large'ish amount of data. Such as if you try to load a web page, etc.
It's as if the packet size limit is suddenly a kilobyte.