Wow, that sounds like the exact opposite of the problem I had a few days ago: http://www.youtube.com/watch?v=S_adeBKPH1Q

Probably completely unrelated, but an odd coincidence anyway.

Wow, yes that is a coincidence and the weirdest thing I ever saw! you know the more i learn about computers the less I understand them! Maybe the developer of that Lotus game developed it with a game port device attached and never tested it with one not connected.

I resolved my issue (sort of) I found one of those PS2 joystick USB adaptors at the back of my drawer and to my surprise it works fine with Windows 98 without and additional drivers, so I'm happy. I'd still like to know why the Gravis drivers affect game speeds though.

Apparently the slowdown tools I used caused that, along with a 'bug' in the game that keeps checking the gameport even if there's nothing connected. See here:
Gameport devices changing PC speed?

Which version of the Xperience drivers were you using by the way? I recall the older versions being less resource intensive than the newer ones. But then it's been years since I last used these drivers (and win9x).
I uploaded my disc (v2.1) to VogonsDrivers last week, maybe you could try that.
Also, does the GrIP mode work with the USB adapter?

Ah ha, was it mo slo by any chance?

I am using version 2.1 as well, the CD ISO.

I didn't explain myself very well, im not using the Gravis with the USB adaptor, but a Playstation 2 Dual shock controller, works just fine in Windows 98 to my surprise. To be honest I think I will just use that, works really well and has the bonus of analog control for games that support it. I will keep the Gravis for pure DOS gaming.

Huh. I'd sooner expect it to be a slowdown related to the Sound Blaster Live (involving its gameport). I had no Gravis Gamepad Pro issues when I used to use it on a much, MUCH slower computer with an AWE64, and I also used the Xperience CD drivers.

I can assure you it's nothing to do with the SB Live, as soon as I uninstall the Gravis drivers, everything is fine, so it has to be that.

As has been asked already, when you were experiencing your problems, were you using the Gravis Gamepad Pro in GrIP mode, or regular mode? There should be a switch on the back.

GrIP mode uses an entirely different method of signalling controller inputs than what Windows or most older DOS games normally expect.

I was using GRIP mode with the drives installed, I also tried it on the other two modes, but the controller was not recognised. With the drivers uninstalled I was kind of able to use the other modes, but could not select some buttons in games.

Have you not wondered what those "other two modes" are..?

If I'm not mistaken, one of them is the "two-controller" mode. This allows two controllers to be plugged in at the same time. It works by disabling two of the buttons.

You could try a newer version of the Xperience drivers, maybe the older version was not so good after all. I really can't remember, and I can't try either since I don't have win9x.

But of course, a PS2 controller with analog controls is much better than the GP Pro 😀