| Dell has rebranded quite a few Broadcom (BCM5820 to name one) SSL PCI Crypto cards. Modern FreeBSD and Linux kernels have complete working support for these. Sometimes, they're known as an "800" card meaning they can do up to 800 signs a second.
In order for these to work, the kernel first must see them. After this, taking advantage of this typically (at time of writing, 20041014) involves compiling openssl with EXPERIMENTAL (Please see http://www.openssl.org documentation) modifications so you may use this. Linux and FreeBSD have kernel level hardware offloading for software VPN (kame, racoon, ipsec, openswan, etc) so you can start to see over 10Mb/s of crypto capability without CPU lag.
Apache with mod_ssl also supports these cards but requires the custom compiled openssl libraries with the experimental option configured.
atr |
Linux on Dell systems FAQ-O-Matic : 
Gigabit Support