Thank you for your message.
A Bluetooth adapter just acts as a radio conduit for the information given it to send by the software in the computer. As such, it operates very quickly. Any lag would be caused by a software, processing, or radio interference issue. Some lag is always present with Bluetooth because of the processing necessary, but it typically happens fast enough that it isn’t noticeable.
It seems likely that the processor isn’t the issue. So I think we should focus on interference.
The best way to check is to use a USB 2.0 extension cable six feet long or so (like this one: https://www.amazon.com/dp/B00NH136GE/) to move the adapter away from the computer and into line of sight with the receiving device.
Some quick points about your troubleshooting plans:
Bluetooth doesn’t troubleshoot like most devices, where you can swap devices from computer to computer or check against known good devices, due to the sensitivity of Windows to any conflict among Bluetooth drivers.
Please don’t uninstall the Windows drivers. The drivers from the website needs them. However, this is not likely to affect the problem, since the drivers on the website add some capabilities, but wouldn’t improve something that is already working. They won’t help lag.
Plugging the adapter into another computer could cause problems for the other computer if it already has a Bluetooth adapter installed and Windows installs the Plugable driver over the existing adapter’s drivers. If the other computer has never had a Bluetooth adapter, then it would be OK.
Buying and installing another adapter can also cause problems unless all the drivers from the Plugable adapter are removed first.
A better plan would be first to eliminate radio interference as the cause, then if that doesn’t help, we will test an adapter here for lag and send it as a replacement.
Also, if at any time, you would rather not continue troubleshooting, let us know, and we can issue a refund and send a prepaid label for returning the adapter.