Buy a C6 card and test it out! Applications load faster, boot time is reduced, any file I/O completes faster, and your pictures are more colorful! (Just kidding about the last one.)
At the same time, outside of recording higher resolution video a laptop with a C2 card is fully functional. Cheers, wad On Aug 18, 2010, at 6:13 AM, Sridhar Dhanapalan wrote: > I am trying to determine whether it is worth us spending this > additional $2-3USD. > > Has anyone tested what the practical difference is when using a C6 > card over a C2? Being able to record at high-res is a good start. What > about general speed and latency for normal use? > > I took a look at the SD and USB FLASH Drive Performance wiki page, but > it isn't clear what the real difference is for classes. > > Thanks, > Sridhar > > > Sridhar Dhanapalan > Technical Manager > One Laptop per Child (OLPC) Australia > p: +61 425 239 701 > w: http://laptop.org.au > > > > On 6 August 2010 09:55, John Watlington <[email protected]> wrote: >> >> Early prototypes are built using a wide range of SD cards: I believe >> we used at least six models in B/C test machines. >> While individual developers usually only have one or two, we >> do make sure that all SKUs are distributed to some software >> developers and testers. Both Quanta and the hardware team >> are careful to test across all prototype SKUs. When we had a >> QA department, they too were testing on all SKUs. >> >> We could place C2 cards in all prototype SKUs, but then Quanta >> would refuse to use C6 cards without further testing. >> >> I've said it before, and I'll say it again. If you want C6 cards, >> you will have to pay to get them. OLPCA pushes Quanta >> for the lowest price, and C2 cards are usually $2-$3 cheaper >> than C6. >> >> BTW, the REAL definition of C2 versus C6 is the resolution >> of video that can be streamed onto the card. So our higher >> resolution video encoding problems using C2 cards shouldn't >> be surprising... >> >> wad >> >> On Aug 5, 2010, at 2:54 PM, Martin Langhoff wrote: >> >>> We recently saw that (at least some) XO-1.5 developer machines (C1, >>> "ramp" units, etc) have SD cards that are significantly faster than >>> what is being shipped to end users. >>> >>> This was a surprise to me (and probably to a few more of us) -- we >>> assumed that most dev machines had a similarly spec'ed SD card to the >>> shipping machines. AIUI, we intended to have an assortment of >>> "candidate" SD cards on the ramp units, the units I've seen all have >>> pretty fast cards :-) >>> >>> This probably explains the scattered results of testing Record >>> audio/video sync -- with lots of 'works for me' vs "definitely doesn't >>> work". The slower SD cards are significantly slower. >>> >>> Deployments can request faster cards (at a cost), but I think it makes >>> sense to test with the lowest common denominator. And we definitely >>> need to understand what SD card is behind each "works" or "doesn't" >>> report re Record and other write-intensive tasks. >>> >>> To aid clarity, Mitch has added a ".speed" test to OFW -- and we've >>> timed a few cards with it: >>> http://wiki.laptop.org/go/SD_and_USB_FLASH_Drive_Performance >>> >>> How to check your internal SD card brand & model: >>> http://wiki.laptop.org/go/XO_Debugging_tips >>> >>> cheers, >>> >>> >>> >>> m >>> -- >>> [email protected] >>> [email protected] -- School Server Architect >>> - ask interesting questions >>> - don't get distracted with shiny stuff - working code first >>> - http://wiki.laptop.org/go/User:Martinlanghoff >>> _______________________________________________ >>> Devel mailing list >>> [email protected] >>> http://lists.laptop.org/listinfo/devel >>> >> >> _______________________________________________ >> Devel mailing list >> [email protected] >> http://lists.laptop.org/listinfo/devel >> > _______________________________________________ Devel mailing list [email protected] http://lists.laptop.org/listinfo/devel
