On Mon, Feb 13, 2012 at 1:20 PM, Jeff Chua <jeff.chua.linux@xxxxxxxxx> wrote: > On Mon, Feb 13, 2012 at 1:16 PM, Jeff Chua <jeff.chua.linux@xxxxxxxxx> wrote: >> On Mon, Feb 13, 2012 at 12:41 PM, Jeff Chua <jeff.chua.linux@xxxxxxxxx> wrote: >>> I ran tests for frequency that works dd out 1G of data from 8MHz to >>> 16MHz, and it seems frequency less than 8.4MHz can only transfer at >>> rate of 14.3MB/s and above 8.4MHz, speed goes up to 18.3 MB/s. Above >>> 17MHz, errors encounters. >>> >>> hz1 8000000 73.5029 s 14.3 MB/s >>> hz2 8000000 73.4740 s 14.3 MB/s >>> hz3 8000000 73.3982 s 14.3 MB/s >>> hz1 8200000 71.9677 s 14.6 MB/s >>> hz2 8200000 73.4936 s 14.3 MB/s >>> hz3 8200000 73.3462 s 14.3 MB/s >>> hz1 8400000 56.6296 s 18.5 MB/s >>> hz2 8400000 56.7616 s 18.5 MB/s >>> hz3 8400000 56.7926 s 18.5 MB/s >>> hz1 8600000 56.6622 s 18.5 MB/s >>> hz2 8600000 56.7201 s 18.5 MB/s >>> hz3 8600000 56.6476 s 18.5 MB/s >>> hz1 8800000 56.8846 s 18.4 MB/s >>> hz2 8800000 56.8226 s 18.5 MB/s >>> hz3 8800000 56.7070 s 18.5 MB/s >> >> I've turned on write, and there's no error writing. But speed is >> slower than accessing it via USB2 SD card reader. Same SD. >> > > Via SD PCI > 18.779 sec 4.04 %cpu > > Via USB2.0 Card Reader > 12.205 sec 2.04 %cpu > > Via USB3.0 Card Reader > 11.427 sec 2.01 %cpu > > > Shouldn't PCI SD be faster? Same SD used for all tests. Are there any thoughts on this or I should give up hope on the SD :(( Or is there something else I should try? Thanks, Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
