Why is 64 bit MATLAB DAQ toolbox slow?

% On 32bit machine running 32 bit Matlab, the function 'getSample' executes faster than its 64bit counterpart, 'inputSingleScan' function. Both commands serve the same purpose, they grab data from channels that I assigned to the DAQ card. The DAQ i m using is National Instruments PCIe 6341.

% How i calculate the loop time and frame rate. the number of iterations doesn't affect the loop time.

num_iter=7000; tic;

for n = 1:num_iter

UPDATE_multiDM(driver_info, VP); % Plus perturbation QP = inputSingleScan(s) ; % Metric measurement UPDATE_multiDM(driver_info,VM); % Minus perturbation QM = inputSingleScan(s) ; % Metric measurement end

toc; loop_time = toc/num_iter frame_rate = 1/loop_time

% with 'getSample' I can achieve a frame rate of 1.4KHz, but only 190Hz with 'inputSingleScan' % What can I do to decrease the execution time for 'inputSingleScan' on my 64bit machine.