High Speed Continuos Acquisition and Lock-in Détection- Producer/Consumer

I have implemented a simple producer consumer to acquire data at 4 MSPS (2 channel) using PCI 6110E and use NI-Lock-in detection. I always end up labview crashing due tomemory error. The queue size keeps increasing. 

I am quite surprized that even if I disable the Lock-in detection and do asimple logging, the system crashes. However, if I have the lock-in detection done in the producer loop, it works perfectly.

I modified the code to use consumer loop to write to csv files the 2 channel data.Again, the queue size keeps increasing. The second image demonstrates the issue. What I see is that producer/consumer cannot run at higher sampling rate very well. Please correct me if I am wrong. 

Also, could you please suggest a solution to the problem?

Thanks