[Sussex] Dell Latitude C640 versus C840

[Frances Fleming]

We've been trying to make up our minds between the two laptops below (no
other possibilities for this particular purchase, because it will be a
trade-in of a C610 purchased from them two months ago).
They are the two top items on
http://www.val-u-computers.co.uk/acatalog/Used_Laptops_from__400____499.html,
unless anyone thinks the Packard Bell Easynote Celerons would be worth
considering. Our IT have explained Celeron and we're not over keen.

Leaving asside the price issue, we want to know what benefits come with
the C840 that will outweigh the terrific weight of the thing as compared
with the smaller and lighter C640.
It will be running a couple of distros and also the Live Knoppix.
Could anyone help us please?

Dell Latitude C640
Pros:
    Lighter
    Better battery life
    Stronger backlight
Cons:
    14" screen
    Only one USB 1.1 port (splitters aren't always satisfactory)


Dell Latitude C840
Pros:
    15" screen
    Two USB ports, not sure if USB2 or 1.1
Cons:
    Very heavy
    Poorer battery life
    Weaker backlight

Other differences:

        C640                      C840
        ----------------------    -------------------------
Weight  2.6 kg (5.7 lb)           3.39 kg (7.48 lb)
Speed   1.7ghz                    1.8ghz
Video   ATI Mobility RADEON 7500C NVIDIA GeForce4 440 Go
Vid mem 32 MB                     64 MB
Max res 1024 x 768                1400 x 1050
Backlite 6.5W (XGA);7.0W (SXGA+)  4.7W using battery;6.2W AC
Memory  266-MHz DDR SDRAM         PC2100 DDR SDRAM
Network 10/100 Ethernet LOM       10/100 Ethernet LAN on board
Battery 3 to 4 hours              2.5 to 3 hours

The links to the full technical specifications.

http://www.val-u-computers.co.uk/acatalog/more/dell_c640_detailed_spec.htm

http://www.val-u-computers.co.uk/acatalog/more/dell_c840_detailed_spec.htm