Hi Vladimir,
AES-NI will certainly help, at least with websites utilizing that in their active cipher suite. The x2 is a rough recommendation; frankly I wouldn't be comfortable doing HTTPS Inspection on a 5400 or smaller box at all unless Internet bandwidth was less than 50Mbps and ended up being the primary performance constraint. Unless the <5400 box has a Falcon accelerator card in it course. 🙂 I doubt the HTTPS Inspection optimizations in R80.20 will help much on a 2-core firewall.
The context of that "less than 4 cores" conversation concerned the fact that if CoreXL is enabled and a firewall has 2 cores, both of them will try to serve "double duty" by acting both as a SND/IRQ core and a Firewall Worker core. This is much less efficient than having each core dedicated to only one function and defeats many of the gains provided by CPU fast caching, as the CPU caches thrash back and forth between the two functions. In some cases disabling CoreXL completely on a 2-core firewall can actually improve the situation, as one core is dedicated to SND/IRQ functions and the other one is the solitary Firewall Worker. No easy way to know for sure ahead of time if disabling CoreXL on a 2-core firewall will help or hurt, just have to try it...
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