Recently I have installed Vista Ultimate 64bit on my note book because I wanted to get the peak performance utilizing the existing hardware resources. Also my target is to run VMware ESX infrastructure on my note book for the R&D purposes. What I have is a HP DV series Core 2 Duo T9300 @ 2.5GHz, 6MB L2 Cash, Bus Speed 800Mhz and 4GB RAM.
(You can get a very basic idea about 64bit http://www.windows-vista-update.com/Windows_Vista_64_bit.html )
I found everything work perfectly with Vista 64bit but Cisco VPN client installation has failed . And then I found Cisco has clearly stated that they don’t have a plan to support VPN client for Vista 64bit.
“There are no current plans to provide 64-bit support for the Cisco VPN Client but 64-bit support is available for the Cisco AnyConnect VPN Client” link: http://www.cisco.com/en/US/products/sw/secursw/ps2308/products_qanda_item09186a00801c2dbe.shtml
And in the other end Microsoft provides VPN clients compatibility summary http://support.microsoft.com/kb/929490
Luckily Cisco AnyConnect VPN client came to picture and I have configured SSL VPN in Cisco ASA 5510 and now my Anyconnect VPN client works perfectly. It’s a SSL tunneling based connectivity and performance improves with DTLS tunneling and also it has many options of performance tuning. Still I didn’t evaluate the performance Vs Cisco VPN client.
Cisco any connect configuration can be found in http://www.ciscosystems.com/en/US/docs/security/vpn_client/anyconnect/anyconnect22/administration/guide/22admin4.html
And Cisco ASDM latest versions provides SSL VPN Wizard and it will make your life easier.