>>Some USR modems have small amounts of non-volatile RAM (e.g. flash RAM) that is used to hold configuration settings. It may be that one or more of these settings is configured to a lower-than-optimal speed. If there is a USR utility setup program it might be able to display and/or let you adjust these settings (if they exist).
>>
>>You could check the details of the property sheets for the modem while it's in each machine; you may find a difference.
>>
>>Driver *may* have an effect, if an OEM driver is being used. Late-model versions of Windows usually support modems from most major vendors natively without any need for an OEM driver.
>>
>>Finally, you could check BIOS settings in each computer. Some innocuous-looking settings like "Plug & Play OS installed?" actually have a major effect on the entire system (former should be set to "Yes" for all Windows OSs newer than NT4) by affecting IRQ assignments etc. Again, you could compare the two nominally "identical" machines and check for BIOS differences.
>
>A sysadmin in my office pointed out what I knew but hadn't thought about, that the "57K" reported by my faster modem has to be the speed at the bus, not over the line. I asked him why I wouldn't see the bus speed on the other machine. He said that there could be a setting somewhere that is different. He suggested that I test the actual speed of these modems using one of these two websites:
>
>
>http://wdc.speakeasy.net/
>
>http://ciseweb100.cise-nsf.gov:7123/

>I expect to check these things out this evening. Perhaps with a result from them, I can go back to Verizon and get them to take a closer look at our phone line, if necessary.

OK, I thought you were already reporting hard speed numbers.

By "speed at the bus" I assume you mean COM port speed. This should always be set to 115,200 for all modems that are not ancient.

The V.90/V.92 standard sets (theoretical) maximum download rate at 56 kilobits per second. In practice I have seen 47-48Kbps under good conditions, I've seen magazine reviews under perfect test equipment conditions of 53Kbps.

If you're using a protocol that compresses, such as ZModem, it could be that the value you're seeing is the effective throughput e.g. 28.5Kbps @ 2:1 compression would be 57Kbps.

There are also 3rd-party products (and some dial-up ISPs) that use speculative link downloading and local content caching to "enhance the Web experience". These typically work by examining links on a page you're currently looking at, and downloading all or parts of them while the line is not otherwise occupied. If you happen to want to go to a page it's already downloaded, you get instant response. If you are making use of any product like that it could also report "effective throughput" higher than you'd expect on a POTS line, and different from the actual line speed.