是Tlistbox的原因，由于把得到的质数同时也往items里加，从而导致内存多使用很多，速度也慢了很多

取消此Tlistbox后，问题均消失：
已经算到了12亿：
2006-08-29 18:07:17.354_1227730627(61780000)d=20.9594(209594/count)delta2=611
2006-08-29 18:07:20.108_1227941647(61790000)d=21.1020(211020/count)delta2=630
2006-08-29 18:07:22.802_1228150967(61800000)d=20.9320(209320/count)delta2=614
2006-08-29 18:07:25.425_1228360547(61810000)d=20.9580(209580/count)delta2=656
2006-08-29 18:07:28.189_1228569493(61820000)d=20.8946(208946/count)delta2=623
2006-08-29 18:07:31.184_1228780843(61830000)d=21.1350(211350/count)delta2=609
2006-08-29 18:07:34.298_1228990561(61840000)d=20.9718(209718/count)delta2=609
2006-08-29 18:07:37.323_1229200169(61850000)d=20.9608(209608/count)delta2=637
2006-08-29 18:07:40.427_1229408503(61860000)d=20.8334(208334/count)delta2=627
2006-08-29 18:07:43.001_1229614931(61870000)d=20.6428(206428/count)delta2=633
2006-08-29 18:07:45.534_1229824801(61880000)d=20.9870(209870/count)delta2=616
2006-08-29 18:07:47.888_1230034571(61890000)d=20.9770(209770/count)delta2=657
2006-08-29 18:07:50.251_1230242557(61900000)d=20.7986(207986/count)delta2=686
2006-08-29 18:07:52.584_1230449459(61910000)d=20.6902(206902/count)delta2=615
2006-08-29 18:07:54.998_1230658397(61920000)d=20.8938(208938/count)delta2=658
2006-08-29 18:07:57.351_1230868109(61930000)d=20.9712(209712/count)delta2=610
2006-08-29 18:07:59.695_1231076491(61940000)d=20.8382(208382/count)delta2=651
2006-08-29 18:08:02.048_1231284889(61950000)d=20.8398(208398/count)delta2=638
2006-08-29 18:08:04.381_1231492723(61960000)d=20.7834(207834/count)delta2=629
2006-08-29 18:08:06.785_1231703701(61970000)d=21.0978(210978/count)delta2=614
2006-08-29 18:08:09.148_1231913021(61980000)d=20.9320(209320/count)delta2=629
2006-08-29 18:08:11.522_1232122649(61990000)d=20.9628(209628/count)delta2=628
2006-08-29 18:08:13.875_1232332807(62000000)d=21.0158(210158/count)delta2=618
2006-08-29 18:08:16.248_1232543287(62010000)d=21.0480(210480/count)delta2=629
2006-08-29 18:08:18.662_1232753869(62020000)d=21.0582(210582/count)delta2=632
2006-08-29 18:08:21.015_1232963339(62030000)d=20.9470(209470/count)delta2=657
2006-08-29 18:08:23.399_1233172961(62040000)d=20.9622(209622/count)delta2=605
2006-08-29 18:08:25.742_1233381649(62050000)d=20.8688(208688/count)delta2=617
2006-08-29 18:08:28.086_1233590627(62060000)d=20.8978(208978/count)delta2=632
2006-08-29 18:08:30.479_1233801133(62070000)d=21.0506(210506/count)delta2=624
2006-08-29 18:08:32.872_1234011703(62080000)d=21.0570(210570/count)delta2=610
2006-08-29 18:08:35.226_1234220279(62090000)d=20.8576(208576/count)delta2=634
2006-08-29 18:08:37.579_1234429783(62100000)d=20.9504(209504/count)delta2=659
2006-08-29 18:08:39.923_1234639849(62110000)d=21.0066(210066/count)delta2=642
2006-08-29 18:08:42.306_1234848877(62120000)d=20.9028(209028/count)delta2=621
2006-08-29 18:08:44.709_1235057233(62130000)d=20.8356(208356/count)delta2=606
2006-08-29 18:08:47.053_1235265403(62140000)d=20.8170(208170/count)delta2=655
2006-08-29 18:08:49.436_1235477041(62150000)d=21.1638(211638/count)delta2=588
2006-08-29 18:08:51.790_1235684987(62160000)d=20.7946(207946/count)delta2=656
2006-08-29 18:08:54.133_1235895281(62170000)d=21.0294(210294/count)delta2=641