Your new server should be a 64-bit machine ... and i never had one so i can only guess
I the Linux OS 64-bit? Then difference in memory requirements are easily
explained - on 64-bit pointers and longs are twice as long as on 32-bit,
and PHP uses both a lot in variables, so memory requirement for huge
array can be significantly bigger on 64-bit OS.
.:: I met php the 03 December 2003 :: Unforgettable day! ::.
Server specs (Server OS / Apache / MySQL / PHP / DragonflyCMS):
CloudLinux / Apache 2.4 LSAPI / MySQLi 5.7 / PHP 7.3 / head
Server Geonis4 (LINUX-CENTOS 5- 1GB memory)
index.php: MYSQL: 18,9 ms; PHP: 90 ms
foros.php: MYSQL: 22,4 ms; PHP: 104 ms
Geonis3 is a Quad-Core AMD Opteron(tm) Processor 1354 - 6GB of memory (the biggest machine)
Geonis2 is a Dual-Core AMD Opteron(tm) Processor 1214 HE - 3GB of memory
Geonis4 is a AMD Athlon(tm) 64 X2 Dual Core Processor 4000+ - 1GB memory