[Nexus One Accessories] houzuoguo:
A month ago I ordered this item:

http://www.amazon.com/Lexar-MicroSD..._m=ATVPDKIKX0DER&pf_rd_r=1PQ8JS4R3GMEAF3KKA5X

Yesterday it arrived, a 32GB, Class 10 MicroSHDC.

Previously I had a Sandisk 16GB Class 2.

Today I'm gonna try it on my Nexus One and keep this thread updated regarding my experience with this card.

Let me post ATTO test result screenshot first

4 May 09:10am Partitioning it, 256MB swap, 2GB ext2, rest = FAT 32

4 May 09:24am Done an ATTO test on my old Sandisk 16GB Class 2 and upload screenshot

4 May 09:27am Preparing for a complete wipe on my Nexus One. Re-format 32GB card using 32KB allocation unit size. Using Windows Explorer to copy and paste music into it, speed is around 9.9MB/s

4 May 09:33am Writing is very steady, at around 9.85MB/s. Finger touched on the card, it's very hot :rolleyes: I'm using Lexar card reader (which came with the card).

4 May 10:19am Just cleaned my phone (physically ;) ) and copied lot of music into the card, gonna put it back into phone and do a clean wipe

4 May 10:59am System boots fine, configuring settings, no noticeable boot speed improvement since I have not installed any app yet.

4 May 11:13am Noticed that the phone's speed of installing & downloading multiple apps at once has increased significantly.

4 May 11:29am Installed about 30 apps system runs smoothly, no any problem so far.

4 May 05:19pm Has been running the phone for half a day, noticed no battery consumption difference, the SD card is stable.

5 May 18:25pm Today I installed more apps (185 in total), and started experiencing serious performance problem, system stuck when listening to music and installing multiple apps. Re-partitioned the SD card into 0 sawp, 1.2GB ext 4 and rest is Fat32, still using 32kb as allocation unit size. I'll see if the issue gets solved. By the way, the battery consumption of the new card seems to be equal as my previous Sandisk one.

6 May 08:47am After re-formatted the card last night and updated to the latest CM nightly, IR's kernel and Gapps, the issue seems to be little better, although it is still laggy to install more than 10 applications at once however the phone does not freeze anymore (so far). Probably 2GB ext partition was too big for DT app2SD?

8 May 10:03am Everything seems to be very stable and fast, partition configuration is: 1.2GB Ext2, 0 Swap, rest = FAT32 using 32KB file allocation unit size, have more than 200 apps installed now.

9 May 15:47pm Well, after installed totally 300 apps yesterday, the system has been not very responsive, applications often lose response and come back after a while, Market app sometimes lose response and crashes, system is pretty unstable. I was on Nightly #64, IR's 0506 kernel and Gapps 0503. I have just re-partitioned the SD card again, trying 1GB Ext2, 0 Swap, rest = FAT 32 and use 16KB as file allocation unit size. This time I'll use CM stable 7.0.3, IR's 0507 kernel and Gapps 0301, see if everything becomes OK.

10 May 13:15 Really tired of re-installing system for more than 4 times in just one week. The card initially performed well but now it just can not handle App2ext, Market app keeps crashing, application forces close and system reboots automatically multiple times every hour. But I don't plan to give up and go back to my old 16GB card yet, I'm seeking for a solution and I'm confident that Nexus One can handle a 32GB sd card.

11 May 09:00 Yesterday I thought about changing the partition characteristics. Eventually I formatted the card into 1.2GB Ext3, 0 Swap, rest = Fat32 using 64KB file allocation unit size and now the stability issue seems to have been resolved, no more force closes or system reboots. Is it the key that 64KB allocation unit size resolved the issue?

11 May 20:00 I've just re-installed (I can't remember how many times I've done this in the last 10 days) system, did a clean and complete wipe and re-partitioned SD card into 1GB Ext3 and rest = Fat32 using 64KB file allocation unit size. I feel like the reason of instability is now determined. Now I'm installing apps and will report back later on stability and make a conclusion with this Class 10 32GB card.

12 May 20:03

Now I can make a conclusion on how to correctly use this card on Nexus One.

There are two factors, which contributed to instability of my previous installs, one is CPU voltage, another is partition layout.

The new card seems to use a bit more voltage to work, that's why my phone became unable to use (reboots and FCs) after I applied my own voltage table (undervolt 100mV at each frequency compare to default table) with IntersectRaven's kernel. The card works fine with the default voltage table of IntersectRaven and CM's kernels.

However, that's not all.

Why the system was very unresponsive when installing many applications, and simple multi tasking would completely freeze the system? Another factor contributed to the issue: File allocation unit size. From the speed test screen shot we can see that the card achieves its best performance when block size is 64KB, that indicates that the card internally is formatted into 64KB blocks. I am still not sure why using 16KB or 32KB file allocation unit size for its FAT32 partition will cause system to be very unstable, however after using 64KB as file allocation unit size, the system runs very smooth and stable, now I'm happy with the card's speed and quality.

Current partition layout:

1 GB Ext 2

0 Swap

Rest = FAT 32 using 64KB as file allocation unit size

18 May

Re-partitioned into 1.5GB Ext2 (1GB was not enough for 400+ apps) and rest=FAT32, still using 64KB as file allocation unit size.

The card has been stable and noticeably fast with more than 400 apps installed.

9 Aug

This card has corrupted for about 7 times due to rapid random accessing by phone, and proven unstable for daily use. Do not use this card on your phone if you have more than 200 apps installed on Ext partition!

See this post for more details:

http://xdaforums.com/showthread.php?t=1209720