SD Card performance - Touch Pro2, Tilt 2 Android General

I've spent the past half a day looking through google and the kernel source code to try to get a better grasp of how to improve the SD performance under XDAndroid. And I think I tracked one of the causes of the slowness, I do need some feedback on how Linux treats various SD cards.
There is a file called /dbgfs/mmc1/ios that contains some data about your SD Card. Unfortunately, it's set to read only by root, so you'll have to copy the content to make copy-and-pasting easier. Using Terminal Emulator, enter the following command:
su
cp /dbgfs/mmc1/ios /sdcard/mmc1.txt
Then use your favorite editor to open the file and copy the content. Please also include the brand, capacity, and class rating of the card to make the information useful.
My card: Kingston 4gb Class 4
clock: 48000000 Hz
vdd: 17 (2.9 ~ 3.0 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 2 (sd high-speed)
Thanks.
-- Starfox

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Samsung class 6, 8GB
Clock: 32000000 Hz
vdd: 17 (2.9 ~ 3.0 v)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 2 (sd high-speed)

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Kingston C4, 8gb
Clock: 32000000 Hz
vdd: 17 (2.9 ~ 3.0 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 2 (sd high-speed)
So far the only difference is clock - is that because you've tweaked that on your startup.txt Starfox..?

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Yeah it's due to setting fmax, I was hoping to come across a non-HS card to see if the clock would be different.
-- Starfox

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Starfox said:
Yeah it's due to setting fmax, I was hoping to come across a non-HS card to see if the clock would be different.
-- Starfox
Click to expand...
Click to collapse
I have several other (older) SD's. I'll post up some info on them - I know at least one of them is a 'brandless' and 'classless' Chinese crapcard.

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HP Class 4, 8GB
clock: 32000000 Hz
vdd: 17 (2.9 ~ 3.0 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 2 (sd high-speed)

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SanDisk C4 4GB MicroSD HC
clock: 25000000 Hz ..............
vdd: 17 (2.9 ~ 3.0 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 0 (legacy) .........
SanDisk 2GB
clock: 25000000 Hz
vdd: 15 (2.7 ~ 2.8 V) ...........
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 0 (legacy)

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Sandisk C4 16GB MiscroSD HC
clock: 25000000 Hz
vdd: 17 (2.9 ~ 3.0 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 0 (legacy)

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Transcend microSDHC Class6 8GB *and* Transcend microSDHC Class10 8GB (from .35)
Code:
clock: 49152000 Hz
vdd: 15 (2.7 ~ 2.8 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 2 (sd high-speed)
Please note, that the "clock:" entry is just what the kernel thinks is in effect. The next lower clock which is selected by clock-wince.c on .27 is 32MHz and on .35 it is 40MHz.
Please verify by enabling "clock_wince.debug_mask=15" and watch the output. I wrote that from the top of my head as I did look into this once. Think I am still right about the lower clocks, though
PS: The Class10 has serious write error issues on .27 and .35. Haven't investigated much further. Dunno if a clock at around 50Mhz could help...

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SanDisk 6GB C4 MicroSDHC Card:
Clock: 32000000 Hz
vdd: 17 (2.9 ~ 3.0 v)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 2 (sd high-speed)

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fishingmedic said:
Sandisk C4 16GB MiscroSD HC
clock: 25000000 Hz
vdd: 17 (2.9 ~ 3.0 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 0 (legacy)
Click to expand...
Click to collapse
This seems realy fishy. 16GB class4 Sandisk shouldn't be using lowspeed. Possible it's one of those "relabeled" one.
Anyway, I got the info I needed, thanks everyone. Upping the speed isn't quite as easy as I thought, but I'll keep everyone posted.
-- Starfox

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Starfox said:
This seems realy fishy. 16GB class4 Sandisk shouldn't be using lowspeed. Possible it's one of those "relabeled" one.
Anyway, I got the info I needed, thanks everyone. Upping the speed isn't quite as easy as I thought, but I'll keep everyone posted.
-- Starfox
Click to expand...
Click to collapse
It's possible, I got it at Walmart but it clearly came in the same packaging that the 16GB cards for $60, but this on a heck of a lot cheaper ($25 IIRC).

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Transcend SDHC Class6 HighSpeed 8GB
A little bit late perhaps, but here's mine:
clock: 48000000 Hz
vdd: 17 (2.9 ~ 3.0 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 2 (sd high-speed)