What is the CPU(s) doing (system monitor) when you make these comparisons?

Edit: On my system using only NAT I got twice the output on the host and CPU was lower than when using the guest. I expect that given the interface is virtualized some performance hit would be normal. 2X is more than I expected. I don't run any services though so really don't care - it's interesting, though. I was using http://www.speedtest.net/ to and from Seattle.

Message was edited by:
dp_fusion

I have to admit I was surprised to read about the very significant speed difference you and others have measured. I know I'm stating the obvious; but NAT in and of itself isn't the source of that.

I'm too lazy to try this right now, but it might be interesting to set up a separate NAT server daemon on the Mac, and to point the virtual machine (bridged) at that. It'd require a bit of monkeying around with the firewall though; and while I've done that with Linux iptables I don't have the experience to do that quickly using ipfw.

One other thing to keep in mind is that the networking is significantly simplified when using NT if you're a laptop user that frequently moves between wireless networks. Under NAT, as VMware/OS X is handling the address assignment to the guest OS's, they don't need to re-authenticate when moving between networks -- only the host OS needs to. Under bridged mode, each guest would also have to authenticate, and get new NAT addresses, etc.

Whether or not this impacts you depends. In my case, my MacBook tends to roam through three different wireless networks over the course of the day -- my home network (which uses WPA2-based authentication), the campus network (which uses 802.1X-based authentication), and my department's network (which uses a web-based authentication scheme). Using NAT, I can kep using VM's as I cross these various network boundries throughout my day without affecting them at all -- they don't need a new IP address, and need do no authentication. If I were to run them all in Bridged mode, I'd have to authenticate against the campus and department wireless networks as I move between them during the day, for each and every guest OS (as well as the OS X host).

Little of which matters for a desktop system, but for a roaming laptop user, NAT mode can certainly reduce a lot of headaches. I can just imagine that in Bridged mode, if you were to stop somewhere with paid WiFi access (like many airports, at least here in Canada), you'd have to pay once per host/guest if you wanted all of them to have network access, whereas in NAT mode only the host needs pay, and everyone else can "ride for free".

Yaz.

Ah, this explains the issue I posted a couple of days ago regarding my slow FTP upload speed. I was in NAT and though I thought it was also happening in Bridged, a couple of tests this evening confirms that while there are slight variations, the problem is definitely with NAT. Bridged mode is currently netting me within a 10% allowance of the speeds I get from FTP with the host Mac, while NAT is off by a factor of about 75%.

As far as I know, that link is the way to report bugs, request support, and make feature requests. You can get to it from vmware.com/mac > Report a Problem, so if it's wrong, the site needs to be corrected.