i was using Apache from last 3 years. never faced a single problem. Few days ago i think to try Nginx. As i heard from mny people. Its very fast memory efficient webserver. Trust me guys. Nginx can never be memory efficient. Rather it consumes memory same like my mozilla. I never understand for what reason it creates a garbage of disk cache for every request.
look at the pic

http://i.imgur.com/pD7rEDe.png

Though i like some features of Nginx like header modification and error 444.

Apart from that Nginx is worst.

My Server configuration:
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 8
On-line CPU(s) list: 0-7
Thread(s) per core: 2
Core(s) per socket: 4
Socket(s): 1
NUMA node(s): 1
Vendor ID: GenuineIntel
CPU family: 6
Model: 58
Model name: Intel(R) Xeon(R) CPU E3-1245 V2 @ 3.40GHz
Stepping: 9
CPU MHz: 1601.453
CPU max MHz: 3800.0000
CPU min MHz: 1600.0000
BogoMIPS: 6784.50
Virtualization: VT-x
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 8192K
NUMA node0 CPU(s): 0-7


I can use 2 Gb ram whole day with apache and with Nginx even 32 gb ram works only for 5 min.

If any of you have any suggestion to tweak nginx config. Please tell me.