Can I increase GPIB performance?

[bubbles]

P3 650MHZ, 256MB Ram, Win98, PCI-GPIB, LabVIEW 6.0.
I am sending the following string via GPIB (VISA) to an Agilent 8648B signal generator in a while loop to increment the output frequency as fast as possible.
":FREQ:CW 10.0MHZ;"
This is working just fine, except that I would like to speed it up a bit. With a delay in the while loop of 85ms it takes 17.1 seconds to execute 200 of the above commands. If I drop the delay time to 35ms, the 200 steps still take 17.1 seconds to complete. No improvement. Is there any way to make it faster?
Thank you.

[cktears]

Could be the speed limit of your signal generator. It takes a while to change the frequency this way. Maybe you can loop up its manual to see if it has the function of sweep or ramp frequency. Using that you only need one GPIB command and give the rest of the work to the generator.

[bubbles]

Yes, this generator has a frequency sweep function, but I need the sweep to be synchronous with a measurement. 42000 frequency steps is taking about an hour and a half to complete. You may be correct about the speed limit of the generator. Thanks