Baixei e parece que melhorou, mas não troquei o pool, vou experimentar o que vc recomendou...
D:\Documentos\vivar\projetos\litecoin\pooler-cpuminer-2.1.2-win32>minerd --url h
ttp://pool.bitlc.net:80 --userpass 5U8KHW:wy5ahV --threads 4
[2012-02-03 18:37:43] Long-polling activated for
http://pool.bitlc.net:80/LP/[2012-02-03 18:37:44] thread 1: 4096 hashes, 3.56 khash/s
[2012-02-03 18:37:45] thread 2: 4096 hashes, 2.62 khash/s
[2012-02-03 18:37:45] thread 0: 4096 hashes, 2.25 khash/s
[2012-02-03 18:37:45] 4 miner threads started, using 'scrypt' algorithm.
[2012-02-03 18:37:47] thread 3: 4096 hashes, 1.47 khash/s
[2012-02-03 18:38:17] thread 3: 82180 hashes, 2.76 khash/s
[2012-02-03 18:38:34] thread 0: 130668 hashes, 2.67 khash/s
[2012-02-03 18:38:37] thread 2: 151987 hashes, 2.94 khash/s
[2012-02-03 18:38:44] thread 3: 63563 hashes, 2.62 khash/s
[2012-02-03 18:38:58] thread 1: 206211 hashes, 2.83 khash/s