looks like swap... can u show
# vm_stat
# top -o faults
# vm_stat
# top -o faults
> vm_stat
Mach Virtual Memory Statistics: (page size of 16384 bytes)
Pages free: 28209.
Pages active: 114788.
Pages inactive: 111624.
Pages speculative: 1301.
Pages throttled: 0.
Pages wired down: 99067.
Pages purgeable: 11340.
"Translation faults": 340573628.
Pages copy-on-write: 8586888.
Pages zero filled: 184635739.
Pages reactivated: 62859723.
Pages purged: 12373577.
File-backed pages: 88759.
Anonymous pages: 138954.
Pages stored in compressor: 645107.
Pages occupied by compressor: 127459.
Decompressions: 62433647.
Compressions: 82841473.
Pageins: 10295559.
Pageouts: 177162.
Swapins: 16692043.
Swapouts: 17670838.
> top -o faults
PID COMMAND %CPU TIME #TH #WQ #PORT MEM PURG CMPRS PGRP PPID STATE BOOSTS %CPU_ME %CPU_OTHRS UID FAULTS COW MSGSENT MSGRECV SYSBSD SYSMACH
533 WindowServer 10.5 06:21:59 21 5 2792- 876M- 209M+ 298M 533 1 sleeping *0[1] 0.17876 1.03550 88 24771383+ 131690 354813610+ 136121938+ 237020876+ 554000668+
2862 Safari 0.0 62:48.95 10 3 7051 480M 6400K 316M 2862 1 sleeping *0[37332] 0.00000 0.00000 501 13919243 76306 67003396 20901240 54405367+ 167230473
2883 com.apple.We 0.0 16:36.04 92 3 926 393M 384K 301M 2883 1 sleeping *19137[3734] 0.00000 0.00000 501 4032470 132 7204377 3215767 45641766+ 32182159
491 mds 0.0 11:00.86 5 2 422 66M 0B 52M 491 1 sleeping *0[1] 0.00000 0.00000 0 3296694 154 6396987 1450677 27494382 5594171
792 mds_stores 0.0 14:00.57 4 2 93- 72M- 16K 61M 792 1 sleeping *0[1] 0.00000 0.00000 0 2786911 1956 4619344+ 1304164+ 15524959+ 4296749+
2694 Terminal 7.6 03:17.73 8 2 311 303M- 37M+ 104M- 2694 1 sleeping *0[6352] 0.85412 0.15218 501 2034254+ 338 1151091+ 265791+ 1517195+ 269400
Mach Virtual Memory Statistics: (page size of 16384 bytes)
Pages free: 14959.
Pages active: 405692.
Pages inactive: 374907.
Pages speculative: 28768.
Pages throttled: 0.
Pages wired down: 91521.
Pages purgeable: 3805.
"Translation faults": 24292564.
Pages copy-on-write: 729689.
Pages zero filled: 14619003.
Pages reactivated: 712889.
Pages purged: 265424.
File-backed pages: 361509.
Anonymous pages: 447858.
Pages stored in compressor: 270669.
Pages occupied by compressor: 93710.
Decompressions: 405581.
Compressions: 790223.
Pageins: 1093581.
Pageouts: 3406.
Swapins: 0.
Swapouts: 0.
PID COMMAND %CPU TIME #TH #WQ #PORT MEM PURG CMPRS PGRP PPID STATE BOOSTS %CPU_ME %CPU_OTHRS UID FAULTS COW MSGSENT MSGRECV SYSBSD SYSMACH CSW PAGEIN
596 firefox 1.8 25:24.36 101 3 4607 1050M- 24M 197M 596 1 sleeping *0[2679] 0.61835 0.00000 501 1801083+ 15982 30520748+ 10145476+ 37431119+ 74055473+ 25506295+ 10499
136 WindowServer 3.8 34:09.24 17 5 2570- 1069M- 3008K+ 84M 136 1 sleeping *0[1] 0.04109 0.69237 88 1554555+ 29134 88175354+ 30598736+ 69071968+ 130099954+ 19109478+ 1791
734 Textual 0.0 01:16.23 9 1 858 144M 16K 25M 734 1 sleeping 0[2051] 0.00000 0.00000 501 833293 1717 745088 111931 478143 1563730 470159 2023
2195 Xcode 0.0 01:43.32 14 1 856 278M 144K 114M 2195 1 sleeping 0[1168] 0.00000 0.00000 501 701255 3278 1626845 546420 1139890+ 1959450 732276+ 148341
2650 Simulator 0.0 01:05.27 4 2 267 27M 0B 8976K 2650 1 sleeping *0[1402] 0.00000 0.00769 501 695662+ 211 755586+ 680393+ 1078007+ 2178634+ 1065718+ 134
539 Terminal 0.6 01:01.28 8 2 304 107M 25M 16M 539 1 sleeping *0[1375+] 0.06887 0.02264 501 582200+ 463 520635+ 71597+ 365523+ 1208051+ 360370+ 1522
2209 SourceKitSer 0.0 00:25.22 2 1 21 714M 0B 468M 2209 1 sleeping 0[672] 0.00000 0.00000 501 473966 51040 3676 1103 1047453 5748 17114 12740
653 Microsoft Re 1.6 13:51.17 33 7 462 536M 12M 148M 653 1 sleeping *0[845] 0.00000 0.00000 501 454751 21517 9976456+ 1770226+ 11942684+ 47364219+ 15135688+ 82
602 plugin-conta 0.0 01:01.70 39 1 278 362M 0B 87M 596 596 sleeping *1[3] 0.00000 0.00000 501 407089 2481 32035 12156 2744155 110109 996847 155
3576 GarageBand 2.7 09:19.30 23 2 822 1088M 16K 664M 3576 1 sleeping *0[288] 0.01295 0.00000 501 266176 2365 7887976+ 76435 9436303+ 19319436+ 18860820+ 930
292 mds_stores 0.2 01:18.32 5 3 95 24M+ 16K 9056K 292 1 sleeping *0[1] 0.00000 0.17381 0 252741+ 93 158368+ 58900+ 1418145+ 178062+ 301682+ 42331
2305 lldb-rpc-ser 0.0 00:18.56 4 1 62 1049M 0B 201M 2305 2195 sleeping \*0[3] 0.00000 0.00000 501 213604 1380 575628 287827 710177 307114 244010 32467
looks like Safari and WindowsServer use swap all the time. try to shutdown at least 1 per day - maybe it will help.