DAQCard-6533 (PCMCIA) Doublebuffered performance

[PM]

I'm using my DaqCard-6533 (PCMCIA) under Win2k (service pack 1) in doublebuffered patterngeneration mode. Laptop specs: 750Mhz PIII with 192mb ram. The manual shows a performance of 120000 S/sec. I get error 10803 when i use the card at any frequency above e few Khz's.
My test program which is attached runs double buffered mode from 2000000 Hz till 1 Hz. On error it changes to a lower frequency. When the program is running and I right-click on the desktop the frequency always lowers ( i always get the 10803 error), not depending on the frequency it is currently running (tested till 6kHz). I know under 4Khz it doesn't always generate this error.
I want to use the DAQCard at 40Khz... the manual shows 120K
hz (on a slower laptop).. so i supposed this should work... But it doesn't. on frequency's higher than 20khz it even produces errors on mouse movement.
So my question is... what's wrong? why can't i read data at the specified benchmark rates. (source attached) (using visual c++ 6.0 whith the NIDEX32.LIB and NIDAQ32.LIB

[bman]

PM

Here are a couple things to check. First, have you tried just using the example program you wrote yours from? This would get rid of any extra overhead your program is causing, though it may not make any difference. Also, the spec you mentioned is for 8-bit operations though your program has GroupSize set to 2, which indicates you are doing 16-bit operations. If you only want to do 8-bit, change the GroupSize to 1. Do you have another PCMCIA card in the computer? If so, try your program with it out. Also, if you are using an older version of NI-DAQ, pre 6.9.1, I would suggest upgrading to the newest versions as there has been some optimization. (The newest one is 6.9.2) Try to adjust the buffer size as well as a larger buffer size sometimes helps decrease
the amount of -10803 errors.

Brian