Data acquisition methods and systems in support of non-snoop transactions. In the data acquisition method, the cache memory is partially written back and invalidate, such that a portion of the data in the cache memory is written back to the DMA buffer. The endpoint device is directed to use a non-snoop transaction to read the data stored in the DMA buffer. The data stored in the DMA buffer is acquired directly without snooping the processor when receiving a non-snoop read transaction.