2000 DDK的Packet例程性能问题请教！！

各位大侠：
    小弟我打算用2000 DDK的Packet例子做东西，先做了个试验，别的什么都没改，就在PacketReceiveIndicate函数前面加上一句return，直接返回了，这样来测试一下Packet的抓包速度，然后用TestApp把Filter设为Directed，全速拷贝文件，然后用DbgView看输出，平均PacketReceiveIndicate每秒收600多个报文，然后设置到混杂模式，每秒收900多个报文，可是我用Sniffer，人家每秒可是1500多没问题啊，我还什么操作没加呢，各位发表一下高见啊！

代码如下
NDIS_STATUS
PacketReceiveIndicate (
    IN NDIS_HANDLE ProtocolBindingContext,
    IN NDIS_HANDLE MacReceiveContext,
    IN PVOID       HeaderBuffer,
    IN UINT        HeaderBufferSize,
    IN PVOID       LookAheadBuffer,
    IN UINT        LookaheadBufferSize,
    IN UINT        PacketSize
    )
/*++

Routine Description:

    PacketReceiveIndicate is called with a pointer to a
    lookahead buffer. If this buffer contains less than
    the full, received network packet, it
    calls NdisTransferData with a protocol-allocated packet
    descriptor specifying protocol-allocated buffer(s) to obtain
    the remainder of the received packet.

Arguments:


Return Value:


--*/
{
    POPEN_INSTANCE      open;
    PIO_STACK_LOCATION  irpSp;
    PIRP                irp;
    PLIST_ENTRY         packetListEntry;
    PNDIS_PACKET        pPacket;
    ULONG               sizeToTransfer;
    NDIS_STATUS         status;
    UINT                bytesTransfered = 0;
    ULONG               bufferLength;
    PPACKET_RESERVED    reserved;
    PMDL                pMdl;

    DebugPrint((\"ReceiveIndicate\\n\"));
    return NDIS_STATUS_SUCCESS;
    //后面原来的代码...
}
然后我在DbgView看输出字串“ReceiveIndicate”，Directed模式每秒就600多个，这可不行啊！各位大侠给个意见奥！