で、いろいろ変えてみる前に、
まずは今の設定での効率を調べて、状況をきちんと把握する

ことから始めようと。

ということで、httping -c 100 -g http://www2.2ch.net/ の結果(cvsup.peko.2ch.netから)

connected to www2.2ch.net:80, seq=73 time=18.44 ms
connected to www2.2ch.net:80, seq=74 time=3014.49 ms
(略)
connected to www2.2ch.net:80, seq=75 time=21.35 ms
timeout receiving reply from host
connected to www2.2ch.net:80, seq=77 time=16.91 ms
connected to www2.2ch.net:80, seq=78 time=14.07 ms
(略)
connected to www2.2ch.net:80, seq=87 time=17.59 ms
connected to www2.2ch.net:80, seq=88 time=11.90 ms
connected to www2.2ch.net:80, seq=89 time=3017.84 ms
connected to www2.2ch.net:80, seq=90 time=3015.85 ms
(略)
connected to www2.2ch.net:80, seq=96 time=471.73 ms
connected to www2.2ch.net:80, seq=97 time=6219.80 ms
connected to www2.2ch.net:80, seq=98 time=15.69 ms
connected to www2.2ch.net:80, seq=99 time=19.33 ms
--- http://www2.2ch.net/ ping statistics ---
100 connects, 99 ok, 1.00% failed
round-trip min/avg/max = 11.7/449.1/6219.8 ms