ESET NOD32 Antivirus 3.0* is a hybrid program in that it contains both 32-bit and 64-bit program code. The engine and interface modules used by ESET NOD32 to protect a system from malware are the result of years of development to create highly-optimized x86 assembly language code. During testing, it was discovered that recompiling certain portions of the program to 64-bit code resulted in increased memory usage with no discernable improvement in performance, stability or reliability.
When a 64-bit interface needs to be monitored, such as for on-access or Windows Socket layer scanning, 64-bit code is used to do so. As evidenced by ESET NOD32's high scanning throughput and detection rate under 64-bit operating systems, this does not cause any complications.
The general rule-of-thumb for ESET NOD32 Antivirus 3.0 is that parts of the program which need to run as 64-bit do, while parts which have no advantage running as 64-bit remain 32-bit code.
