You need more ram, and ditch the hard drive, top of the line high IOPS SSD's only
How much space do I need in the ssd?Is 63GB or 128GB enough?
Quad core is okay for running multiple currency pools?
Don't think only about the pool, think also about the coin daemon.
For example, with this 9 coins :
du -sh .b* .f*|grep -v bash
621M .bbqcoin
53M .bitbar
22G .bitcoin
11M .bosscoin
1.1G .fastcoin
411M .feathercoin
303M .florincoin
226M .franko
130M .freicoin
The BlockChain cost a lot of I/O, and a lot of ram to start the daemon.
If you want to run only one coin, you can put everything in RAM.
For example, runing a pool (slush pool for scrypt)
Pool# cat /proc/2897/status |grep -i vmsize
VmSize: 291324 kB
For worldcoin with ~50 miners
The daemon:
cat /proc/8920/status /proc/27455/status|grep -i vmsize
VmSize: 586732 kB
VmSize: 508384 kB
I run two daemon as a security.
So for example, in that case it's arround 1.5G RAM.
You can put the blockchain in the Ramdisk to earn more speed (speed will help you to prevent orphans blocks).