Citat:
Ursprungligen inskrivet av -Boris-
Vem bryr sig om vilka förbättringar dom gjort som inte syns. Det enda som påverkar mig är det jag ser. Och jag kan inte se en enda ny funktion i vista som jag kommer dra nytta av. Varför ska jag då uppgradera?
DX10 är bara ett lockbete. För det kunde dom släppt till XP också.
då kan jag rekommendera dig att läsa på lite ...
du kan ju börja här:
http://en.wikipedia.org/wiki/Technical_features_new_to_Window...
vista erbjuder väldigt många förbättringar som är varmtvälkommna!
här är ett urklipp angående nätverksprestanda :
Network performance
Windows Vista Networking stack also uses several performance optimizations, which allow higher throughput by allowing faster recovery from packet losses, when using a high packet loss environment such as wireless networks. Windows Vista use the NewReno algorithm which allows a sender to send more data while retrying in case it receives a partial acknowledgement, which is acknowledgement from the receiver for only a part of data that has been received. It also uses Selective Acknowledgements (SACK) to reduce the amount of data to be retransmitted in case a portion of the data sent was not received correctly. It also includes Neighbour Unreachability Detection capability in both IPv4 and IPv6, which tracks the accessibility of neighboring nodes. This allows faster error recovery, in case a neighboring node fails.
Another significant change that aims to improve network throughput is the automatic resizing of TCP Receive window. The receive window (RWIN) specifies how much data a host is prepared to receive, and is limited by, among other things, the available buffer space. Receive window auto tuning functionality continually monitors the bandwidth and the latency of TCP connections individually and optimize the receive window for each connection. The window size will be increased in high-bandwidth (~5 Mbit/s+) or high-latency (>10ms) situations. When the receive window is too small, the remote transmitter will frequently find that it has transmitted as much data as the window indicates the local computer is prepared to receive, and is still awaiting an acknowledgment to permit further transmission. This leads to incomplete link utilisation. As such a larger window allows more efficient bandwidth utilisation.
In previous versions of Windows, all processing needed to receive or transfer data over one network interface was done by a single processor, even in a multi processor system. Windows Vista can distribute the job of traffic processing in network communication among multiple processors. This feature is called Receive Side Scaling. Windows Vista also supports network cards with TCP Offload Engine, that have certain hardware-accelerated TCP/IP-related functionality. Windows Vista uses its TCP Chimney Offload system to offload to such cards framing, routing, error-correction and acknowledgement and retransmission jobs required in TCP. However, for application compatibility, only TCP data transfer functionality is offloaded to the NIC, not TCP connection setup. This will remove some load from the CPU. Traffic processing in both IPv4 and IPv6 can be offloaded. Windows Vista also supports NetDMA, which uses the DMA engine to allow processors to be freed from the hassles of moving data between network card data buffers and application buffers. It requires specific hardware DMA architectures, such as Intel I/O Acceleration to be enabled.
Traditional TCP implementations uses the TCP Slow Start algorithm to detect how fast it can transmit without choking the receiver (or intermediate nodes). In a nutshell, it specifies that transmission should start at a slow rate, by transmitting a few packets. This number is controlled by the Congestion window - which specifies the number of outstanding packets that has been transmitted but for which an acknowldgement of receipt from the receiver has not yet been received. As acknowledgements are received, the congestion window is expanded, one TCP segment at a time till an acknowledgement fails to arrive. Then the sender assumes that with the congestion window size of that instant, the network gets congested. However, a high bandwidth network can sustain a quite large congestion window without choking up. The slow start algorithm can take quite some time to reach that threshold - leaving the network under-utilized for a significant time. Windows Vista TCP/IP stack includes a component called Compound TCP (CTCP) which, if enabled, uses a different algorithm to modify the congestion window - borrowing from TCP Vegas and TCP New Reno. For every acknowledgement received, it increases the congestion window more aggressively, thus reaching the peak throughput much faster, increasing overall throughput.[16]
The new TCP/IP stack also supports Explicit Congestion Notification (ECN) to keep throughput hit due to network congestion as low as possible. Without ECN, a TCP message segment is dropped by some router when if its buffer is full. The sender detects the segment did not reach the destination; but due to lack of feedback from the congested router has no information on the extent of reduction in transmission rate it needs to make. Standard TCP implementations detect this drop when they time out waiting for acknowledgement from the receiver. The sender then resets the size of its congestion window, which denotes the amount of data allowed to be unacknowledged by the sender at any time, to TCP's Maximum Segment Size, and commences TCP Slow Start. This is to let the router recover from congestion. However, the sudden drop in throughput rate has noticeable impacts on time-sensitive streams like streaming media, and such a significant drop might not have been necessary. In that case, the bandwidth available is being left under-utilized. With ECN support enabled, the router sets two bits in the data packets that indicate the receiver it is experiencing congestion (but not yet fully choked). The receiver in turns lets the reciever know that a router is facing congestion and then the receiver lowers its transmission rate by some amount. If the router is still congested, it will set the bits again, and eventually the sender will slow down even more. The advantage of this approach is that the router does not get full enough to drop packets, and thus the sender does not have to lower the transmission rate significantly to cause serious delays in time-sensitive streams; nor does it risk severe under-utilization of bandwidth. The only caveat is that both sender and receiver, as well as all intermediate routers, have to be ECN-enabled. If any of them is not ECN-enabled, they might consider a ECN-marked packet invalid and drop them. For this reason, ECN is disabled by default. It can be enabled via the netsh interface tcp set global ecncapability=enabled command.[17]