> ale pasirodo buna laptopai su dviem hdd, totalus battery sink saltinis :)

ale zinok ne :D.. kodel?.. ogi HDD niam niam pakanka per USB, t.y. 5V 0.5A = 2.5W max..

WD 750GB 7200rpm 2.5" ( WD7500BPKT) :
Read/Write 1.75 Watts ..  Idle 0.80 Watts

Hitachi 750GB 7200rpm 2.5"
http://www.hitachigst.com/internal-drives/mobile/travelstar/travelstar-7k750
Requirement: Read/Write (W, avg)  1.8W
Requirement: Low power idle (W, avg)  0.69W
Dissipation: Seek (W, Avg)  2.0W
Performance Idle  1.7W
Requirement: Start-up (W, peak, max)  5.5W << hmm.. 2xUSB tokiam kaip ir reiketu..

*******

~2.0W per HDD ne idle, o darbiniam rezime .. Jei 5400rpm - na bus kokiais 0.5W maziau..

Imam energy-friendly laptop'ika.. na ciupinejes V131 su LV Celeron'u 1.1GHz dual core..
Akumas 65Wh, laiko ~6.5h .. Aida64 rodo, kad eda jis 10W .. tai viskas true..
Jame 320GB 7200rpm HDD berods.. su dviem HDD, jei +2W.. 6,5h * 10W/h / 12W/h = 5.4h
Antras HDD kainuotu akumo valanda !!!! .. siaubas :) .. o jei koks XPS'as?..

http://www.notebookcheck.net/Review-Dell-XPS-17-Notebook-i7-2630QM-GT-555M.51949.0.html
In comparison to other high performance multimedia laptops, such as the Acer Aspire 7750G,
the XPS 17's power consumption is surprisingly high. 25.6 – 39.1 watts in idle mode and 102.3 – 121.8 watt
during load sooner correlate to the power requirement of a full-fledged gaming laptop (e.g. see Asus G73SW).

The hard disk provides a perfect performance. Dell has supplied our test device with a
ST9500420AS from Seagate – a 500 GB HDD with a speed of 7200 rpm.

Tai prie 25.6W idle jei pridet dar viena HDD, tai butu visi 27W ..
90Wh/25.6W=3,52h su vienu HDD, tai su dviem bus - 90Wh/27.6W=3,26h
0.26h * 60min = ~16minuciu laikys maziau :)

Taigi jei ne koks ultra-low-voltage-super-light-ultra-portable
(pvz. jei butu koks nors 4cell - 24Wh akumas ir apetitas 4W/h - laiko 6h, tai 6W/h = 4h),
tai antras HDD akumui itara daro, bet tikrai ne tokiau jau didele..
jei piktas laptop (pvz. XPS) tai antras HDD nebus tas, kad bus jame "battery sink source" :D